Cycle-finite module categories

We describe the structure of module categories of finite dimensional algebras over an algebraically closed field for which the cycles of nonzero nonisomorphisms between indecomposable finite dimensional modules are finite (do not belong to the infinite Jacobson radical of the module category). Moreover, geometric and homological properties of these module categories are exhibited

Microstructure and magnetic properties of BaFe12O19 powder

Purpose: Analysis of microstructure and magnetic properties of BaFe12O19 powder obtained by milling and annealing of Fe2O3 and BaCO3 precursors. Design/methodology/approach: The mixture of iron oxide (Fe2O3) and barium carbonate (BaCO3) powders was used to obtain BaFe12O19 powder by using high-energy ball milling and heat treatment processes. The X-ray diffraction methods were used for qualitative, quantitative phase analyses and for crystallite size and lattice distortion determination. The thermal properties of the studied powders were analyzed using the differential thermal analysis (DTA). The magnetic properties of examined powder material were studied by resonance vibrating sample magnetometer (R-VSM). The size of powder particles was determined by a laser particle analyzer. Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray diffraction investigations of Fe2O3 and BaCO3 mixture milled for 50 hours and annealed at 850, 900, 950 and 1000°C enabled the identification of hard magnetic BaFe12O19 phase and also small amount of Fe2O3 phase. The magnetic properties of studied powders are dependent on temperature of their annealing. The sample annealed at 1000°C has the best hard magnetic properties from all studied samples. The content changes of hard magnetic phase (BaFe12O19) with the increase of annealing temperature results in the improvement of hard magnetic properties. Practical implications: The BaFe12O19 powder can be suitable component to produce sintered hard magnetic materials. Originality/value: The study results of BaFe12O19 powders confirm the utility of applied investigation methods in the microstructure and magnetic properties analysis of powder materials. Keywords: X-ray phase analysis; R-VSM; High-energy ball milling; Bariu

Krull Dimension of Tame Generalized Multicoil Algebras

We determine the Krull dimension of the module category of finite dimensional tame generalized multicoil algebras over an algebraically closed field, which are domestic

Fire analysis of structures in terms of physical phenomena observed during uniaxial tensile tests of steel

Metody obliczeń konstrukcji budowlanych w pożarze powinny umożliwiać dokładną analizę i uwzględniać specyficzne właściwości ogrzewanych materiałów, na przykład nieliniowe pełzanie metali. Teoretyczne rozważania na temat konstrukcji metalowych w pożarze mogą być weryfikowane, a także uzupełniane wynikami badań materiałowych i badań ogniowych. Badania materiałów konstrukcyjnych w podwyższonej temperaturze mają na celu przede wszystkim wyznaczenie charakterystyk wytrzymałościowych i termicznych. Wyniki typowych badań ogniowych określają natomiast reakcję elementu wydzielonego z konstrukcji budowlanej na ogrzewanie zgodne z normową krzywą „temperaturaczas”. Normowe uproszczenia rzeczywistych sytuacji pożarowych wynikają między innymi z ograniczonych możliwości badań laboratoryjnych.Calculation Methods for building structures in fire should allow a thorough analysis and take into account the specific characteristics of heated materials such as steel's non-linear creep. Theoretical consideration about metal structures in a fire might be verified and supplemented by the results of the material and fire tests. The main objectives of the research on structure material at elevated temperature is to assign the strength and thermal characteristics. The results of the standard fire tests determine the reaction of the element separated from a structure on the heating according to a standard curve ‘temperature-time”. The standard reduction of the real fire scenarios results, among the others, from the limited opportunities of the laboratory testing

Modelowanie procesów wytrzymałościowych stali S235JR w podwyższonej temperaturze

The article discusses the issue of fire safety of construction steel structures. At the same time it presents the origins of steel properties analysis in the aspect of the extraordinary fire load and a corresponding research position. Results of laboratory tests of steel S235JR at elevated temperature are presented, along with the statistical verification of the description of strength characteristics. Conclusions were drawn with reference to the needs that result from the procedures of structural fire design

Wpływ warstwy tytanu na przeciwelektrodzie na parametry elektryczne DSSC

In this paper the influence of the Ti layer thickness at counter-electrode on electrical parameters of DSSCs was examined. The transparent conductive oxide – less (TCO-less) counter electrodes (CE) with titanium layers and platinum as catalyst on Bk7 glass were prepared. Thin metallic films were deposited by means of magnetron sputtering (titanium) and Pulsed Laser Deposition (platinum). The counter electrode with Pt layer on Fluorine doped Tin Oxide (FTO) were used as reference PV cells. The obtained results indicated that the Ti coated cathodes may be used in transparent conductive oxide – less (TCO-less) dye sensitized solar cells as an alternative for Pt/FTO system.W przedstawionej pracy zbadano wpływ grubości warstwy Ti na przeciwelektrodzie na parametry elektryczne DSSC. Przygotowano nieprzezroczyste przeciwelektrody typu Transparent Conductive Oxide – less z warstwami tytanu na szkle Bk7 oraz FTO i platyny jako katalizatora. Cienkie filmy zostały osadzane na przeciwelektrodach z zastosowaniem rozpylania magnetronowego (Ti) oraz metodą osadzania za pomocą impulsów lasera (ang. Pulsed Laser Deposition, PLD) (Pt). Ogniwa z przeciwelektrodą z warstwą Pt naniesioną bezpośrednio na FTO zostały wykorzystane jako układy referencyjne. Uzyskane wyniki wskazują, że przeciwelektrody z warstwą Ti mogą być stosowane w barwnikowych ogniwach fotowoltaicznych typu TCO-less jako alternatywa dla standardowego systemu Pt/FTO