Knowledge of the temperature distribution in subsurface layers of the ground is important in the design, modelling and exploitation of ground heat exchangers. In this work a mathematical model of heat transfer in the ground is presented. The model is based on the solution of the equation of transient heat transfer in a semi-infinite medium. In the boundary condition on the surface of the ground radiation fluxes (short- and long-wave), convective heat flux and evaporative heat flux are taken into account. Based on the developed model, calculations were carried out to determine the impact of climatic conditions and the physical properties of the ground on the parameters of the Carslaw-Jeager equation. Example results of calculated yearly courses of the daily average temperature of the surface of the ground and the amount of particular heat fluxes on the ground surface are presented. The compatibility of ground temperature measurements at different depths with the results obtained from the Carslaw–Jaeger equation is evaluated. It was found that the temperature distribution in the ground and its variability in time can be calculated with good accuracy.
In the summer of 1979, in South Spitsbergen investigations of the extreme temperatures of the ground surface were carried out. The investigations permitted the determination of the magnitude of the extreme temperatures of the ground surface and their relation to the air temperature. The spatial variability of the extreme temperatures of the ground surface was observed.
It was expected that there would be a relationship between plant density and arrangement within soybean plantations and ground beetles due to changes of abiotic habitat conditions. The aim of this study was to determinate the effect of different plant arrangements of soybean plants on the abundance and species diversity of ground beetles (Coleoptera, Carabidae). The studies were conducted from 2015 to 2017 at the Experimental Research Station, Wrocław, Poland. The occurrence of beetles was examined on soybeans, growing in four different treatments: row spacing of 15 cm or 30 cm, and seeding density of 50 or 90 seeds per m2. The experiment was conducted in a split-plot design in four replicates. Ground beetles were collected with 16 pitfall traps, with one trap in the middle part of each plot. The obtained results show that the general number of ground beetles was similar between the treatments. Some minor effects were found in species number, which was higher in the lower row spacing treatment. Only less abundant species were significantly affected. The most abundant species in all years and treatments were Pseudoophonus rufipes, Harpalus affinis, Calathus fuscipes and Pterostichus melanarius. The abundance of the above-listed common ground beetle species did not differ significantly between treatments.
This paper presents a suggested approach for forensic investigation of bridge decks in which Ground penetrating radar (GPR) consisting of two antennas is used to assess the current conditions. The methodology was tested on a bridge deck in central Sicily. The acquired data were analyzed for identifying the asphalt overlay thickness, concrete cover depth and deck thickness and location of the rebar reinforcement. In the proposed approach for assessing bridge deck conditions the GPR survey was complemented with (i) a site investigation on layer thicknesses for calibration/verification purposes of the GPR response and (ii) a Terrestrial Laser Scanning system (TLS) to verify the bridge design slab curvature. The study shows that this methodology has significant merits on accurately assessing such bridge deck components when bridge design records are non-existing, and by using non-invasive methods such as laser scanning and GPR. The great advantage provided by the TLS technique is the possibility to obtain a 3D output model of the scanned element with the accuracy of the best topographic instruments in order to complement GPR data surveys for bridge inspection.
The arc suppression coil determines whether it can effectively extinguish the arc when it is grounded in the neutral non-effective grounding system. An artificial grounding test is an importantway to verify its performance. In this study, 13 substations with the 10 kV system in the Ningxia areawere selected and considered. Based on the artificial single-phase grounding test, the residual current, the compensation current and the off-resonance degree were measured in the arc suppression coil, and the performance of the arc suppression coil in the 10 kV system was verified. The experimental results show that the error of arc suppression coil automatic measurement is large, the off-resonance degree is large, the resistive component in the compensation current is excessive, the harmonic component exists in the compensating current and capacitive current. To solve these problems, this paper puts forward the corresponding countermeasures for reference.
There are approx. 250 coal waste dumping grounds in Poland, yet there are countries in which this number is even higher. One of the largest sites for depositing mining and power plant waste in the Upper Silesian Coal Basin is the Przezchlebie dumping ground. In the article, it is considered as a secondary deposit of raw materials. An assessment of mining waste collected on the Przezchlebie dumping ground was carried out in terms of its impact on the environment and the possibility of its use. Mining waste samples were tested to determine their chemical composition. Physicochemical properties and chemical compositions of water extracts obtained from the investigated waste and groundwater in the vicinity of the dumping ground were analyzed. Due to the fire hazard resulting from the natural oxidation process of chiefly carbonaceous matter and pyrite, the thermal condition of the dumping ground was assessed. The results of the obtained tests confirmed the slight impact of mining waste deposited on the Przezchlebie dumping ground on the environment. The chemical composition, low radioactive activity of waste itself and the results of water extract tests referred to the permissible values according to the Polish Journal of Laws allow for multi-directional waste management. Due to the significant carbon content, the risk of self-ignition poses a significant threat on the dumping ground. Re-mining of the dumping ground and the recovery of raw materials, including coal contained in waste, will eliminate the risk of fire, allowing for a wider use of waste and, at the same time, will allow for other benefits, e.g. in the form of financial resources and the possibility of managing the dumping ground area.
There was done an inventarization of 41 coal mining dumping grounds, gathering waste material from 27 mines. Considering the fact, that five mines belong to multi-motion plants the research comprised 32 hard coal deposits. Source data with localization of particular dumps have been obtained from archival materials from the mines and municipalities, in the boundaries where the dumps occur as well as free accessible published materials (books, scientific papers). The data have been verified, in the beginning on the basis of topographical maps, orthophotomaps and aerial photographs and then, after vision done during field works they have been drawn on the topographic base, what resulted in creating the map of post-mining dumping grounds. Valorisation of coal mining waste dumps, using already repeatedly presented method, included defining of: name of the dump, coal mine from where the wastes come from, state of the dump, surface of the dump, type of technical and biological reclamation, accessibility of the object, possibilities of recovery of coal and the results have been drawn on the map. On the basis of collected and elaborated data there was done an attempt of defining of potential possibilities of recovery of coal from the dumps and connecting of coal quality in exploited deposits and coal content in waste material. The results showed that in spite of initial information that the majority of the dumps comprise potential objects of coal recovery of coal from waste material, eventually only in some cases (thirteen objects) the recovery seems to be economically justified.
Along the paper the new method called Invertebrate Bankfull Assessment method (IBA method) of determination of bankfull discharge is presented. The investigation of bankfull discharge using IBA were performed within one Polish Carpathian stream in the mountain region: the Ochotnica Stream. As an index of bankfull the existence of certain species of invertebrates was used which are present and resistant to specific water discharge conditions. The borders within a cross section of the mountain stream with a gravel bed were defined where characteristic invertebrates are present which are recognized as bankfull borders. Finally three invertebrates benches (IB-ms) were recognized which are characterized by very specific invertebrate species. Bankfull discharge was calculated up to this IB-ms and corelated using Canonical Correspondence Analysis with other values of bankfull calculated for a cross section using different bankfull.
The paper presents analytical relationships based on the theory of Green’s functions. The relationships refer to instantaneous and continuous as well as point and ring heat sources which are discussed. The relationship relating to continuous ring source is the basis for modelling and designing of spiral ground heat exchangers. Heat transfer in the infinite and semi-infinite body was considered. In the latter case, the image method was discussed. Using the results of measurements regarding heat transfer in the ground with a heat exchanger in the form of a single coil installed, a comparison of calculated ground temperatures with measured values was presented.
In Polish coal mining, medium voltage power distribution networks operate with an insulated neutral point. Zero-sequence current transformers are the basic sensors that generate input signals for earth-fault protection relays. In the literature, the problem of frequency response analysis of various types of current transformers has been examined many times, e.g. [1] [2], but not for zero-sequence current transformers so far. As part of the work, two types of zero-sequence current transformers in the range from 0.1 Hz to 100 kHz were tested. Both the change of the current ratio and the angular shift between the transformer secondary current and the total primary current were analyzed.
Sophie de Grouchy in her Letters on sympathy analyses the notion of sympathy, as a starting point using a critique of Adam Smith’s Theory of Moral Sentiments. She also points out that sympathising with other people’s joys brings us pleasure, other people’s good experiences make us happy (especially if we are the ones who contribute to their well-being) and we want to see other people happy and not suffering. As she assumes, we naturally seek other people’s well-being and not their harm. De Grouchy underlines the role of imagination and reason, discerning coincidental good deeds and those that are an effect of intended actions. The paper aims to reconstruct a way in which de Grouchy seeks the grounds for morality in sympathy that is based on feeling and observation of physical pain and pleasure. This presentation of her theory that Polish readers are not closely accustomed with is a good starting point to inquire whether the argumentation presented by the author of the Letters on sympathy is coherent within her theory and whether it has proper justification.