F codes

The notion of an F code is introduced as a generalization of the notion of an L code. All interrelations between ordinary codes of bounded delay, L codes of bounded delay and F codes are established. Attention is also focused on unary morphisms. Many of them are F codes

Air pollution in Krakow : a glance into the future from a historical perspective

High concentrations of air pollution probably occurred in Krakow in the nineteenth and early twentieth centuries. Since the late 1960s due to the development of monitoring networks level of air pollution is well documented. In the past few decades, a considerable drop in SO_{2} concentration has been observed in conjunction with a major increase in the particulate matter and nitrogen oxides concentrations. The complex composition of aerosol particle samples (quartz, feldspars, clay minerals, carbonates, sulphates, chlorides, aluminosilicate and iron or iron oxide spherules of industrial origin and soot) suggests the multiplicity of their sources. In the near future, increased concentration of very fine particles and precursors of photochemical smog should be expected because of increasing emission from vehicle engines

Distribution of minor metallic elements within waste incineration bottom ashes defined by WDX/EDX spectrometry

A number of metallic elements are inherited from waste during thermal treatment and concentrated in the incineration residues. Because the major part of the incineration residue mass are bottom ashes (BAs), their study is of great importance from the point of view of their environmental impact or resource potential. The general focus of this study was on the minor metallic elements present in BAs. They co-occurred with main phases and often determined the inherited potential of the material. The analysed residues were produced from municipal and industrial waste. The BAs were studied using spectroscopic methods of chemical microanalysis: energy dispersive X-ray spectrometry (EDX) and wavelength dispersive X-ray spectrometry (WDX). Both the main and minor metallic elements were concentrated in metallic components. They were typically present as separate grains and metallic inclusions (commonly in the glass matrix of the grains) ranging in size from several to hundreds of micrometres. Despite Fe-, Al- and Cu-rich occurrences, metallic elements rarely occurred in fragments composed of a single element. Their main forms of occurrence were alloy grains, admixtures in polymetallic occurrences and micro-inclusions in glassy matrix. The content of particular elements in those forms was investigated and described in greater detail. Even though two types of bottom ash were formed from different types of waste and differences in used technologies were present, the obtained materials contained metallic components having similar attributes. Elevated concentrations of not only Fe and Al, but also Ti, Cu and Zn, allow us to consider bottom ash as a promising material from the point of view of metallic elements' recovery (e.g. by the physical concentration of elements through gravity or magnetic methods)

Structural, magnetic and electronic properties of Re-based double perovskites

Este trabajo recoge la caracterización estructural y el estudio de las propiedades magnéticas de muestras de dobles perovskitas basadas en Re: la serie A2FeReO6 (donde A = Ba, Sr o Ca), el compuesto Sr2CrReO6 puro y la serie Sr2-xLnxCrReO6 (con Ln = La, Nd o Sm). Para ello se han utilizado varias técnicas experimentales (tanto macroscópicas como de sonda local) que están explicadas detalladamente en la parte introductoria. El volumen contiene también una introducción teórica en la que se explican varios fenómenos físicos, importantes para las propiedades físicas de los compuestos estudiados

Characteristics of particulate matter emitted from a coal-fired power plant

Particulate matter (PM) emitted into the atmosphere from a hard coal-fired power plant equipped with a pulverised fuel boiler was studied using X-ray diffractometry (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and scanning electron microscopy fitted with X-ray energy-dispersive spectrometry (SEM-EDS). The PM emitted from coal-fired power plants is rarely studied, in contrast to fly ash collected during flue gas cleaning. The material of PM is composed of particles differing in size, morphology, and chemical composition. Aluminosilicate spherical particles dominate, but other particles also occur (irregular aluminosilicate particles, char particles, irregular particles of quartz, Fe oxides, particles rich in Fe, Cr and Ni, barite, and others). The size of other particles varies from 50 \mu m to 250 \mu m. The emitted PM is strongly enriched in several elements in comparison to average coal ash or upper continental crust (e.g., Ag, Bi, Cd, Cr, Hg, Mo, Ni, Re, Se, and Zn). The content of bioavailable, water-soluble fraction (containing S, Ca, K, Na, Cl and subordinate Zn and Ni) is ca 5%. The broad variation of the size and composition of the emitted PM indicates the potential environmental impact and possibility of dispersion over a large area

Airborne magnetic technoparticles in soils as a record of Anthropocene

Airborne magnetic particles in soils were studied in sites located in various distances to industrial plants. Chemical and mineral composition of soil samples were analysed. The highest values of the Pollution Load Index (PLI) calculated for several elements were noted for sites relatively distant from industrial plants. Soil samples exposed for the deposition of airborne particles were examined by means of magnetization versus an external applied magnetic field as well as ^{52}Fe Mössbauer spectroscopy measurements showing a lack of correlation of the magnetic properties with total Fe content, which points toward a strong impact of the industrial activities. Magnetic fraction was extracted and studied using scanning electron microscopy with energy dispersive spectrometry. Two types of spherical particles were noted. Massive ones occurring in all sites and particles with a complex internal structure more abundant in sites situated closer to industrial plants. The presence of spherical magnetic particles formed in high temperature processes indicate their relatively long range transport in the atmosphere. Broad distribution, characteristic and easy for identification spherical form of these magnetic technoparticles, suggest that one can consider them as a record of the Anthropocene. Accumulation of such technoparticles is related to rapid industrialization in the post-World War II period

Iron metallurgy slags as a potential source of critical elements : Nb, Ta and REE

The recovery of valuable metals from metallurgical slag disposals is a promising option to protect natural resources, limited due to technology development and increased consumption. The Ad-hoc Working Group on Defining Critical Raw Materials within the Raw Materials Supply Group has proposed a list of critical elements which have the greatest economic importance and meet the requirements of sustainable development in Europe. The goal of this study was to examine steelmaking- and blast-furnace slags from metallurgical processes to determine concentrations of elements of the greatest criticality for Poland, e.g. Nb, Ta and REE, and to discuss the viability of their recovery. Slag analyses indicate enrichment of REE relative to UCC, NASC and average chondrite compositions in blast-furnace slags and Nb and Ta in steelmaking slags. To make recovery of these critical elements reasonable and profitable, it is recommended that they be recovered together with other useful raw materials

Neural networks in recognition of handwriting

Artificial neural networks consist of many simple elements capable of processing data. These are tools inspired by the construction of the human brain, used in machine learning. The aim of the research was to analyze the occuracy of the created neural network in the process of handwriting recognition. The article presents the results obtained during the learning and testing of a convolution network with a different number of hidden layers. Each time learning and testing the network was carried out using the same set of images (taken from the publicly available IAM database) depicting handwritten words in English