Thermodynamics of quark matter with multiquark clusters in an effective Beth-Uhlenbeck type approach

We describe multiquark clusters in quark matter within a Beth-Uhlenbeck approach in a background gluon field coupled to the underlying chiral quark dynamics using the Polyakov gauge which establishes the center symmetry of color SU(3) that suppresses colored states as an aspect of confinement. Quark confinement is modeled by a large quark mass in vacuum motivated by a confining density functional approach. A multiquark cluster containing $n$ quarks and antiquarks is described as a binary composite of smaller subclusters $n_1$ and $n_2$ ($n_1+n_2=n$). It has a spectrum consisting of a bound state and a scattering state continuum. For the corresponding cluster-cluster phase shifts we discuss simple ans\"atze that capture the Mott dissociation of clusters as a function of temperature and chemical potential. We go beyond the simple "step-up-step-down" model that ignores continuum correlations and introduce an improved model that includes them in a generic form. In order to explain the model, we restrict ourselves here to the cases where the cluster size is $1 \le n \le 6$. A striking result is the suppression of the abundance of colored multiquark clusters at low temperatures by the coupling to the Polyakov loop and their importance for a quantitative description of lattice QCD thermodynamics at non-vanishing baryochemical potentials. An important ingredient are Polyakov-loop generalized distribution functions of $n$-quark clusters which are derived here for the first time. Within our approach we calculate thermodynamic properties such as baryon density and entropy. We demonstrate that the limits of a hadron resonance gas at low temperatures and $\mathcal{O}(g^2)$ perturbative QCD at high temperatures are correctly reproduced. A comparison with lattice calculations shows that our model is able to give a unified, systematic approach to describe properties of the quark-gluon-hadron system.Comment: 20 pages, 11 figures, 6 table

The Evolution of Cognitive Load Theory and the Measurement of Its Intrinsic, Extraneous and Germane Loads: A Review

Cognitive Load Theory has been conceived for supporting instructional design through the use of the construct of cognitive load. This is believed to be built upon three types of load: intrinsic, extraneous and germane. Although Cognitive Load Theory and its assumptions are clear and well-known, its three types of load have been going through a continuous investigation and re-definition. Additionally, it is still not clear whether these are independent and can be added to each other towards an overall measure of load. The purpose of this research is to inform the reader about the theoretical evolution of Cognitive Load Theory as well as the measurement techniques and measures emerged for its cognitive load types. It also synthesises the main critiques of scholars and the scientific value of the theory from a rationalist and structuralist perspective

Analysis of damage of rail vehicles type 31WE due to wild animals on track

W artykule omówione zostały przypadki kolizji ze zwierzyną leśną wybranej grupy pojazdów typu 31WE Kolei Dolnośląskich. Przedstawione zostały zarejestrowane uszkodzenia pojazdów, które następnie zostały powiązane z rozwiązaniami konstrukcyjnymi zastosowanymi w pojazdach. Uszkodzenia zostały skategoryzowane zgodnie z zaleceniami normy PN-EN 50126.Paper discussed the cases of collisions between group of rail vehicles type 31WE of Koleje Dolnośląskie (Lower Silesian Railways) and wild animals. The cases of damage done to rolling stock were presented and discussed with respect of construction of the vehicles. The damages were splitted into categories according to the standard PN-EN 50126

Analysis of damage of rail vehicles type 31WE due to wild animals on track

W artykule omówione zostały przypadki kolizji ze zwierzyną leśną wybranej grupy pojazdów typu 31WE Kolei Dolnośląskich. Przedstawione zostały zarejestrowane uszkodzenia pojazdów, które następnie zostały powiązane z rozwiązaniami konstrukcyjnymi zastosowanymi w pojazdach. Uszkodzenia zostały skategoryzowane zgodnie z zaleceniami normy PN-EN 50126.Paper discussed the cases of collisions between group of rail vehicles type 31WE of Koleje Dolnośląskie (Lower Silesian Railways) and wild animals. The cases of damage done to rolling stock were presented and discussed with respect of construction of the vehicles. The damages were splitted into categories according to the standard PN-EN 50126

Application for educational purposes of programs related to activities of railway undertakings operating passenger services

W artykule przedstawiono podstawowe informacje dotyczące planowania obiegów taboru oraz realizacji procesu przewozowego na kolei. Opisano dwa programy komputerowe związane z działalnością pasażerskich przewoźników kolejowych. Program Traafik, wykorzystywany na kolejach estońskich, ułatwia planowanie obiegów taboru i umożliwia ich przedstawienie w postaci dyspozytorskiego rozkładu jazdy oraz schematycznej mapki. Symulator Pojazdów Szynowych MaSzyna jest instalowany na stanowiskach szkoleniowych dla maszynistów. Oba programy mogą być wykorzystywane na zajęciach ze studentami uczelni wyższych.In the paper basic information on trainset rosterings and realization of railway transportation process was presented. Two computer programs related to activities of railway undertakings operating passenger services were described.. Program Traafik, used on Estonian railways, facilitates planning of rosterings and can show the output in a form of a dispatcher timetable or a schematic map. Railway Vehicles’ Simulator MaSzyna is being installed in training centers for train drivers. Both programs can also be used for work with university students

Management of risks associated with pedestrians in the area of the main railway station in Poznan

Obszarem analiz w tym artykule jest węzeł komunikacyjny Poznań Główny. Na podstawie wybranego przystanku zaprezentowano procedury: rozpoznawania źródeł zagrożeń, grupowania źródeł zagrożeń, formułowania zagrożeń, szacowania ryzyka zagrożeń i wartościowania ryzyka. Są to jedne ze szczegółowych procedur analizy ryzyka w modelu TRANS-RISK. Wykazano ważność tych procedur w zarządzaniu ryzykiem zagrożeń na przykładzie węzła komunikacyjnego Poznań Główny.The main railway station in Poznan (Poznan Główny) is a major transportation hub in the city and therefore it can be used as a valuable area for risk assessment. One of the tram stops located within the hub has been used to perform four main procedures used in TRANS-RISK model: recognition of threats' sources, grouping of threats' sources, formulation of threats and valuation of risk. The procedures have been described and their importance has been proved