The most worldwide method of liquidating underground hard coal mines is by spontaneous flooding as the result of the discontinuation of the rock mass drainage. Due to the hydrological reconstruction of the previously disturbed water system by mining operations, the movements of the rock mass with the opposite direction than subsidence appear. These movements are called rock mass uplift. This paper aims to present possible hazards related to land surface objects and the environment, which can appear during the flooding of the underground mine. The issue of proper forecasting of this phenomenon has so far been marginal in world literature. To date, only a few analytical methods have been used to predict the possible effects of surface deformation. Nowadays, the most common analytical method of forecasting surface deformation caused by the liquidation of underground workings by flooding is Sroka’s method. In this paper, the authors have presented analyses of flooding scenarios developed for a Polish mine and their impact on the land surface as well as the environment. The scenarios presented in the manuscript were selected for analysis as the most probable concerning the mine and the future plans of the mining enterprise. The process of flooding coal mines results in several risks for surface objects and underground infrastructure. This is why the uplift caused by the flooding of the mine should be predicted. The resulting uplifting movements can also, apart continuous deformation lead to the creation of much more dangerous phenomena involving discontinuous deformations.

Due to its location, Puck Bay is an area particularly vulnerable to pollution of anthropogenic origin. The aim of the study was to assess the water quality of small watercourses entering the inner part of Puck Bay. The paper presents the results of chemical and microbiological analyses of 10 rivers and canals at their estuaries located on the western shore of the internal Puck Bay. The following environmental parameters were analyzed: conductivity, pH, dissolved oxygen concentration (in situ measurements), COD (cuvette tests), concentrations of ions (ion chromatography). Microbiological analysis included assessment of sanitary condition based on the number of fecal coliforms by a cultivation method. The determination of basic microbiological parameters such as: prokaryotic cell abundance expressed as total cells number (TCN), prokaryotic cell biovolume expressed as average cell volume (ACV), the prokaryotic biomass (PB) and prokaryotic cell morphotype diversity were determined using epifluorescence microscopy method. Based on the obtained results, it was found that small watercourses may carry a notable load of anthropogenic pollution and thus affect the environment of Puck Bay. The results clearly indicate the need for quality monitoring in the rivers and canals in the Coastal Landscape Park, flowing into Puck Bay. The research showed that also smaller watercourses may have an impact on the coastal waters’ state, and thus on the Baltic Sea water quality.

To test the potential harmfulness of soils fertilized with sludge-based products to plant organisms, a biotest method using the physiological/biochemical reaction of the organisms to assess their toxicity was chosen. This paper presents the results of a preliminary ecotoxicological study of different products: a sludge-based fertilizer, a plant growth promoter, and a reclamation blend. The study was conducted using Sinapis alba L., a plant used in agriculture for intercropping and recommended for toxicological testing. Toxicity tests were performed in a gradient of concentrations of the indicated products (2.5%, 5%, and 10%). For comparison purposes, a trial containing a commercial fertilizer was used alongside the control soil (without additives). The fertilizer and the crop support agent were of low toxicity, but data analysis indicated toxicity of the so-called reclamation blend, which contained heavy metals among other things. The test products showed an increase in toxicity with the increasing dose used. This research represents an important step in assessing the usefulness of products created from sewage sludge and may help overcome the „psychological barrier” that prevents potential investors from investing capital that would allow production to spread.

The Directive on National Emission Ceilings specifies the reduction of ammonia (NH 3) emissions among other air pollutants, which is most significant for the agricultural sector. The ammonia emission limit set for Hungary was a 10% reduction by 2020, while the target of 32% should be reached by 2030 compared to the 2005 reference year. The paper presents the results of a survey on pig production technology in Hungary from 97 domestic farms. The study aims to know the level of implementation of reduction techniques in livestock production and manure management and highlights the need for further improvements in this production sector. The research found that the application of ammonia reduction techniques was not considered widespread, either in livestock buildings or in manure storage (treatment) and during field application. For almost all (more than 90%) pig production groups, the housing systems were the reference without additional emission reduction. For manure storage, farms have insulated storage under the current regulation, however, significantly more emission reduction technologies were in the variant without cover or crust. Slurry spreading was mainly used with manure application techniques, but more emission-friendly injection and band spreading were also emerging. Besides the expected immediate incorporation, a high proportion of manure was applied between 12 and 24 hours or even after 24 hours. In the studied elements of manure management, significant improvements are needed in applying techniques to reduce ammonia emissions. Effective results can be achieved even by shortening the time between manure application and incorporation with efficient work organization.

Climate change, manifested by long term periods of drought to heavy rainfall, may remarkably modify river flow regimes. We hypothesize that flow prevailing in a given year determines water chemistry of the Carpathian Raba River above and below Dobczyce Reservoir (southern Poland), used for drinking purposes. Based on the mean annual river flow for years 1991‒2017, hydrologically dry (HD), hydrologically average (HA)and hydrologically wet (HW) years were distinguished. We found significant differences in the values of most studied physicochemical parameters of river water above and below the reservoir between studied hydrological years (for a period of April‒November). In HD years, the water above the dam had significantly higher temperature and values of conductivity (point pollution source, groundwater inflow), while lower ones of nutrients NO3- and P-tot (diffuse pollution) compared to those in HA and/or HW years. The best GLM models for mean monthly flows above and below the dam include 3‒5 factors among which conductivity and NO3- concentration were always present. The reservoir in different ways influences the water chemistry below the dam in HD, HA and HWyears. The impact of flow on the water quality in hydrologically varied years is discussed. The obtained results are important for appropriate management in catchment basins of mountain rivers and the protection of dam reservoirs against the eutrophication processes in changing climate and flow regime.

The purpose of this research was to determine the groundwater intrinsic vulnerability to pollution of shallow groundwater in Wielkopolska Province, Poland and to assess the risk of pollution by nitrates. Wielkopolska is known as an area where the problem of water pollution by nitrates has existed for a long time due to intensive agriculture. DRASTIC method and its optimized version as well as four other risk evaluation methods were selected to assess the risk pollution with nitrates. The results of either method did not correlate with nitrate concentrations recorded inthe total of 1679 groundwater monitoring points. Therefore a new method of groundwater pollution risk assessment (NV-L) was proposed. The new method is based on optimized results of the DRASTIC system and the L parameter which considers not only land use types, but also the amount of nitrogen loading leached from soil as a result of fertilizer consumption, and from wet deposition. The final results of NV-L method showed that the largest part of the study area is covered by a very low class of pollution risk (30.6%). The high and very high classes occupy 11.6% of the area, mostly in the areas designated until 2012 as the Nitrate Vulnerable Zones. Validation of the results of all methods showed that the other methods than NV-L cannot be used as a basis for reliable assessment of the risk of groundwater pollution by nitrates, as they do not take into account the nitrogen load leached from the soil profile.

As part of the work, experiments were carried out on a laboratory scale to assess the effectiveness of the use of composite capsules based on halloysite and sodium alginate for the adsorption of copper from rainwater. The halloysite was subjected to acid activation prior to the encapsulation process. The characteristics of the capsules obtained were determined by means of SEM surface imaging, nitrogen adsorption by the BET method and pH PZC measurement by the suspension method. Adsorption was studied using various operational parameters such as adsorbent dose, contact time, pH and concentration of copper ions in the rainwater. A high percentage of copper ions removal was demonstrated, i.e. 72% for halloysite (H), and 83% for activated halloysite (HA) for a dose of 2.0 g/L. Adsorption of Cu (II) was consistent with pseudo-second order kinetics. The adsorbents showed a high adsorption capacity at the level of 11.03 mg/g, determined by the Langmuir isotherm model. This model fit well with the experimental data.

High voltage DC insulation plays an important role, especially in power transmission systems (HVDC) but also increasingly on medium voltage levels (MVDC). The space charge behavior under DC voltage has great importance on electrical insulation reliability. This paper reports investigations of encapsulated space charge in homo-multilayer dielectric materials using the pulsed electro-acoustic (PEA) method. The charge has been introduced on the homo-layer interface by corona sprinkling prior to encapsulation. Two doses of charge density were accumulated on the dielectric surface in two types of dielectric materials Kapton and LDPE. The polarization DC voltage was applied in 2 min intervals in steps corresponding to an effective electric field strength in a range of 8-40 kV/mm for Kapton and 10-50 kV/mm for LDPE. The PEA-based detected space charge was compared at the initial, reference stage, prior to charge accumulation, and after corona sprinkling of defined charge density. The evaluation was based on the PEA time-dependent charge distributions and charge profiles referring to the DC polarization field strength. The goal of the experiment was to identify the relationship and the character of the known sprinkled and encapsulated charge inside homo-layered materials using the PEA method. According to the observations, the ratio between sprinkled charge densities is proportional to the encapsulated, charge densities measured by the PEA method on the interfacial homo-layer for the Kapton specimen. In the case of LDPE, a fast decrease of interfacial charge was observed, especially at a higher polarization field above 10 kV/mm. The encapsulation of the known charge amount can be extended to different types of multilayer material. The presented methodology might be used also for extended calibration of the PEA measurement system.

The implementations of matrix multiplication on contemporary, vector-oriented, and multicore-oriented computer hardware are very carefully designed and optimized with respect to their efficiency, due to the essential significance of that operation in other science and engineering domains. Consequently, the available implementations are very fast and it is a natural desire to take advantage of the efficiency of those implementations in other problems, both matrix and nonmatrix. Such an approach is often called a black box matrix computation paradigm in the literature on the subject. In this article, we gathered a broad series of algorithms taking advantage of the efficiency of fast matrix multiplication algorithms in other mathematical and computer science operations.

An active inerter-based suspension with acceleration feedback control is proposed in this paper, the time delay generated in the controllers and actuators is considered, which constitutes the time-delayed active inerter-based (TDA-IB) suspension. The dynamic equation of the TDA-IB suspension is established and is a neutral type of delay differential equation (NDDE) in which the time delay exists in the highest-order derivative. The stability analysis is conducted by calculating the number of unstable characteristic roots based on the definite integral stability method, the stable and unstable regions are determined. The effect of time delay and feedback gain on the dynamic performance of the TDA-IB suspension under harmonic, random, and shock excitations is studied in detail and compared with the parallel-connected inerter-based (PC-IB) and traditional suspensions. The results show that the TDA-IB suspension is asymptotically stable for smaller feedback gain and time delay, through increasing the feedback gain, the stable regions shrink, and a smaller time delay could cause the system to become unstable. Furthermore, the time delay could regulate the resonance peak around the unsprung mass natural frequency and generate multiple high-frequency resonance peaks. If the time delay is chosen appropriately and falls into the stable range, the TDA-IB suspension could improve the dynamic performance for the suspension stroke and dynamic tire load while having a deterioration for the vehicle body acceleration compared with the PC-IB and traditional suspensions.

The overall efficiency of battery energy storage systems (BESSs) strongly depends on the temperature uniformity of the batteries, usually disregarded in studies of the integrated performance of BESSs. This paper presents a new battery thermal management system (BTMS) using a personalized air supply instead of a central air supply. Thermal models are established to predict the thermal behavior of BESSs with 400 battery packs. Moreover, several optimizations comprising the effect of the position and number of air inlets, the number, and angle of the baffles on the air distribution in the ducts are proposed. The results show that the distributed air supply from the main air inlet makes the air velocity in the main air ducts more uniform. It is demonstrated that air deflection is the main source of airflow inhomogeneity at the air outlets. The airflow uniformity is better when the baffles are added at the entrance and the bottom of each riser duct than at other locations. The improved air supply scheme makes the nonuniformity coefficient of air velocity reduced from 1.358 to 0.257. The findings can guide the selection of a cooling form to enhance the safety of BESSs.

HVAC systems use a substantial part of the whole energy usage of buildings. The optimizing of their operation can greatly affect the power use of a building, making them an interesting subject when trying to save energy. However, this should not affect the comfort of the people inside. Many approaches aim to optimize the operation of the heating and cooling system; in this paper, we present an approach to steer the heat pumps to reduce energy usage while aiming to maintain a certain level of comfort. For this purpose, we employ a market-based distributed method for power-balancing. To maintain the comfort level, the market-based distributed system assigns each device a cost-curve, parametrized with the current temperature of the room. This allows the cost to reflect the urgency of the HVAC operation. This approach was tested in a real-world environment: we use 10 heat pumps responsible for temperature control in 10 comparable-sized rooms. The test was performed for 3 months in summer. We limited the total peak power, and the algorithm balanced the consumption of the heat pumps with the available supply. The experiments showed that the system successfully managed to operate within the limit (lowering peak usage), and - to a certain point - reduce the cost without significantly deteriorating the working conditions of the occupants of the rooms. This test allowed us to estimate the minimal peak power requirement for the tested set-up that will still keep the room temperatures in or close to comfortable levels. The experiments show that a fully distributed market-based approach with parametrized cost functions can be used to limit peak usage while maintaining temperatures.

The asymptotic stability of positive descriptor continuous-time and discrete-time linear systems is considered. New sufficient conditions for stability of positive descriptor linear systems are established. The efficiency of the new stability conditions are demonstrated on numerical examples of continuous-time and discrete-time linear systems.