Potential Applications of Vitrified Slag as a Product of Plasma Arc Melting

The present article presents the potential of vitrified slag, one of the products of plasma arc melting, for further industrial applications based on previous experiments. The existing publications on the investigation into this field is hence supplemented with our series of experiments conducted using vitrified slag from plasma arc gasification and melting of fly ash from municipal waste, as well as a mixture consisting of fly ash produced by fluidised-bed boilers in a heat power plant and recovered asbestos cement roofing sheets. It should be noted that the process of plasma arc gasification and melting facilitates not only a significant reduction of the quantity of processed hazardous wastes, but also a possibility of transforming such wastes into an inert product, which may be used as an input raw material in certain industrial processes

Tribological test of compressor used in the refrigeration industry

The article describes the analytical procedures and acceptance criteria for analysis of compressor and components with a focus to tribological aspects. In the introduction, the article deals with tribology as a scientific discipline. Subsequently, the article describes different kinds of wear, which may occur during the operation of compressor at different levels. Subsequently, the article mentions the equipment used in the test. At the end the results of the test are summarized with complete photo-documentation

The Assessment of the Environmental Impact of Selected Plastics

The present article deals with a method of the environmental Life Cycle Assessment (LCA) as a tool for the evaluation of environmental burden of selected products. The assessment of the life cycle of individual products should be carried out while considering emissions released during production, use and disposal of products and during processes of raw material extraction, production of materials and energy, auxiliary processes or sub-processes.   

Gas Transmission System Optimization with Natural Gas Transportation

<p><i><strong>Abstract</strong></i><strong>—</strong> <i>In connection with the heated political situation to the east of the European Union (EU) borders, there is a growing interest in the discovery of new reserves of natural gas or new suppliers of this fossil fuel. This situation consequently requires new and unconventional ways of solving the storage and transportation of gas in large quantities and over long distances. The following article discusses the methods of storage and transportation of natural gas through the gas network.</i></p&gt

Design and calculation of heat transfer of the passive cooling modules for low-pressure hydrogen vessels

This paper deals with the issue of improving the temperature management of a metal hydride tank to reduce the energy intensity of cooling. The problem of absorption and adsorption of hydrogen gas in metals, cooling of metal hydride tanks in the process of hydrogen absorption while protecting the current level of development of science and research for this area is analysed. The work also deals with numerical and experimental verification of a prototype metal hydride tank with passive cooling

A Newly Proposed Method for Hydrogen Storage in a Metal Hydride Storage Tank Intended for Maritime and Inland Shipping

The utilisation of hydrogen in ships has important potential in terms of achieving the decarbonisation of waterway transport, which produces approximately 3% of the world’s total emissions. However, the utilisation of hydrogen drives in maritime and inland shipping is conditioned by the efficient and safe storage of hydrogen as an energy carrier on ship decks. Regardless of the type, the constructional design and the purpose of the aforesaid vessels, the preferred method for hydrogen storage on ships is currently high-pressure storage, with an operating pressure of the fuel storage tanks amounting to tens of MPa. Alternative methods for hydrogen storage include storing the hydrogen in its liquid form, or in hydrides as adsorbed hydrogen and reformed fuels. In the present article, a method for hydrogen storage in metal hydrides is discussed, particularly in a certified low-pressure metal hydride storage tank—the MNTZV-159. The article also analyses the 2D heat conduction in a transversal cross-section of the MNTZV-159 storage tank, for the purpose of creating a final design of the shape of a heat exchanger (intensifier) that will help to shorten the total time of hydrogen absorption into the alloy, i.e., the filling process. Based on the performed 3D calculations for heat conduction, the optimisation and implementation of the intensifier into the internal volume of a metal hydride alloy will increase the performance efficiency of the shell heat exchanger of the MNTZV-159 storage tank. The optimised design increased the cooling power by 46.1%, which shortened the refuelling time by 41% to 2351 s. During that time, the cooling system, which comprised the newly designed internal heat transfer intensifier, was capable of eliminating the total heat from the surface of the storage tank, thus preventing a pressure increase above the allowable value of 30 bar

Oxidative Stress in Animal Models of Acute and Chronic Renal Failure

Introduction. Kidney disease is a worldwide health and economic burden, with rising prevalence. The search for biomarkers for earlier and more effective disease screening and monitoring is needed. Oxidative stress has been linked to both, acute kidney injury (AKI) and chronic kidney disease (CKD). The aim of our study was to investigate whether the concentrations of systemic markers of oxidative stress and antioxidant status are affected by AKI and CKD, and to identify potential biomarkers. Methods. In adult male Wistar rats, AKI was induced by bilateral nephrectomy, and CKD was induced by 5/6 nephrectomy. Blood was collected 48 hours after surgery in AKI and 6 months after surgery in CKD. Advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS), advanced glycation end products (AGEs), fructosamine, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP) were measured. Results. Impaired renal function was confirmed by high concentrations of plasma creatinine and urea in AKI and CKD animals. AOPP and fructosamine were higher by 100% and 54% in AKI, respectively, and by 100% and 199% in CKD, respectively, when compared to corresponding control groups. Similarly, there was approximately a twofold increase in AGEs (by 92%) and TAC (by 102%) during AKI. In CKD, concentrations of FRAP, as an antioxidative status marker, were doubled (by 107%) when compared to the control group, but concentration of TAC, another marker of antioxidative status, did not differ between the groups. Conclusions. AKI and CKD led to increased systemic oxidative stress. AOPP and fructosamine could be considered potential biomarkers for both, acute and chronic kidney damage. On the other hand, AGEs, TAC, and FRAP seem to be disease specific, which could help to differentiate between acute and chronic kidney injuries. However, this needs further validation in clinical studies