Among the numerous modern, high-efficiency energy technologies allowing for the conversion of chemical energy of coal into electricity and heat, the Direct Carbon Fuel Cells (DCFC) deserve special attention. These are devices that allow, as the only one among all types of fuel cells, to directly convert the chemical energy contained in solid fuel (coal) into electricity. In addition, they are characterized by high efficiency and low emission of pollutants. The paper reviews and discusses previous research and development works, both around the world and in Poland, into the technology of direct carbon fuel cells with an alkaline (hydroxide) electrolyte.

The circular economy model is based on several priority areas, including biomass and bio-based products. Focusing on them and their use should certainly take their cascading into account use, including how energy from waste from the wood industry is managed. Biomass is one of the most frequently used renewable energy sources in Poland, and in the European Union it satisfies 6% of primary energy. The CE (Circular Economy) model assumes that the reuse, processing and regeneration of a product requires less resources and energy, and is more economical than conventional material recycling, as low quality raw materials. The current model of waste management must take energy recovery into account, without which it is impossible to close the balance sheet of management of many groups of waste. This is also important from the economic point of view. Chemical energy, which is contained in a large part of waste, can be used for energy purposes, including the production of electricity and heat. Reducing the use of raw materials is the most effective environmental approach to solving the waste problem. However, this requires reducing the extraction and consumption of materials, challenging existing production and consumption patterns. In the circular economy model there is a huge difference in approach to recycling leading to new products that create transport and production, new jobs and possible GDP (Gross Domestic Product) growth. The aim of the study is to analyze the use of waste from the wood industry and to present possible solutions for its cascade use, taking the currently implemented circular economy model (CE) into account.

Running a business entails various risks which can significantly impact the economic and production results achieved by a given enterprise. One way of hedging certain risks is to use appropriately designed derivatives. This article presents the newest group of these contracts, i.e. swaps, and focuses on how these contracts can be used by Polish mining companies from the hard coal mining sector selling a part of their output on the global market. This article briefly characterises and presents types of swaps as well as the Polish swap market, pioneered by Polski Bank Rozwoju S.A. with the first FX swap of 1992. Since then, other types of transactions have also been included in the offering of domestic banks (assets swaps, cross-currency interest rate swaps). Mining companies producing hard coal have not been active on the swap market yet because of their poor activity on derivative markets. This article proposes a swap as an derivative hedging the hard coal price for a mining company exporting a part of its production to the global market. In the presented example, a mining company, by concluding a forward and an appropriately structured commodity swap, was able to both protect it self from a fall in the price and use additional gains due to prices rising in the global market. Apart from commodity swaps, mining companies can use FX swaps, IRS and other swaps described in the literature and commonly applied in practice by various economic entities, depending on the type of risk that needs hedging. A significant advantage of this kind of contract is that there is no need to freeze funds in security deposits, nor are there fees of other kinds (premiums) like those payable for other derivatives (futures, options).

The cement production process is associated with the emission of dust. These are mainly CKD (cement kiln dust) and BPD (by-pass dust), classified as wastes from group 10 – Wastes from thermal processes, subgroups 10 and 13 – wastes from manufacture of cement, lime and plaster and articles and products made from them. Cement kiln dust is a waste of variable composition and properties, which makes it a difficult material to recover. The main directions of recovery presented in the world literature indicate the use of dust from cement kilns in cement, mortar and concrete production, the production of bricks and in order to improve soil quality and wastewater treatment. Factors affecting chemical and phase compositions of dust from cement kilns are the reason why each waste should be analyzed individually. The paper presents the results of the analysis of the cement kiln dust after dedusting cement kilns and two bypass dusts. Analysis of the chemical composition has shown significant concentrations of chlorine, potassium and calcium in all wastes. The content of: Si, S, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Zr, Pb, and Bi has also been confirmed. The analyzed dusts were characterized by the presence of carbonates (calcite, dolomite, and arcanite), quartz, alite, belite, sylvine, anhydrite, and portlandite in their phase composition. The leachates which were characterized by an alkaline reaction. In terms of leachability, high concentrations of chlorine ions in the analyzed dust leachates were confirmed, which significantly limits their use.

The paper presents a modification of capillary optical fibers fabrication method from an assembled glass preform. A change of dimensional proportions in the capillary optical fiber drawn from a single preform is allowed on-line via the control of overpressure and thermal conditions in the outflow meniscus which essentially lowers the manufacturing costs. These conditions are among the solutions (velocity fields) of the Navier-Stokes equations adapted to the capillary optical fiber pulling geometry and temperature distribution in the oven. The velocity fields give solutions to other quantities of interest such as flow rate, pulling force and fiber geometry. The calculation and experimental results for capillary optical fibers were shown in the following dimensional range: internal diameters 2-200 µm, external diameters 30-350 µm, within the assumed dimensional stability (including ellipticity) better than 1%. The parameters of fabricated capillary optical fibers of high-quality low-loss optical multicomponent glasses were: losses 100 dB/km, mechanical strength above 1GPa with Weibull coeffcient in the range 3-7, internal numerical aperture 0.1-0.3, external numerical aperture 0.1-0.3, core index 1.5-1.8, transparency 0.4-2 µm, thermally and/or chemically conditioned internal surface, double polyimide protection layer, soft or hard jacketed, connectorized. The capillary optical fibers were applied in our own and several external laboratories in spectroscopy, refractometry, micro-fluidics and functional microoptic components. The paper summarizes a design, technological and application work on capillary optical fibers performed during a recent national research program devoted to optoelectronic components and modules.