Features of the resources of the hard coal covering in thin coal-seams in Poland

The results of analyses of features of geological resources of the hard coal, in majority of mine located in Poland, were presented, according to adopted arbitrarily criteria. All active mines of the hard in the Silesia voivodship were provided with analysis.Результати аналізів особливостей геологічних ресурсів кам'яного вугілля, в більшості шахт Польщі, були представлені згідно довільно прийнятим критеріям. Були проаналізовані всі діючі кам'яновугільні шахти воєводства Сілесія.Результаты анализов особенностей геологических ресурсов каменного угля, в большинстве шахт Польши, были представлены согласно произвольно принятым критериям. Были проанализированы все действующие каменноугольные шахты воеводства Силесия

Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia

Background and aims: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. Methods: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m−2 yr.−1, 353 μg l−1), Whixall Moss (1.37 g m−2 yr.−1, 1505 μg l−1). The total N amount per plant and the contributions of prey/root N to the plants’ N budget were calculated using a single isotope natural abundance method. Results: Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed – Cors Fochno plants captured 62% greater proportions of Diptera. Conclusions: Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance

Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

The removal of Cr(III) ions and methylene blue (MB) from aqueous solutions by xanthated corn cob (xCC) in batch conditions was investigated. The sorption capacity of xCC strongly depended of the pH, and increase when the pH rises. The kinetics was well fitted by pseudo-second order and Chrastil’s model. Sorption of Cr(III) ions and MB on xCC was rapid during the first 20 min of contact time and, thereafter, the biosorption rate decrease gradually until reaching equilibrium. The maximum sorption capacity of 17.13 and 83.89 mg g-1 for Cr(III) ions and MB, respectively was obtained at 40 °C, pH 5 and sorbent dose 4 g dm-3 for removal of Cr(III) ions and 1 g dm-3 for removal of MB. The prediction of purification process was successfully carried out and the verification of theoretically calculated amounts of sorbent was confirmed by using packed-bed column laboratory system with recirculation of the aqueous phase. The wastewater from chrome plating industry was successfully purified, i.e. after 40 min concentration of Cr(III) ions was decreased lower than 0.1 mg dm-3. Also, removal of MB from the river water was successfully carried out and after 40 min removal efficiency was about 94 %

Predicting the capability of carboxylated cellulose nanowhiskers for the remediation of copper from water using response surface methodology (RSM) and artificial neural network (ANN) models

This study observed the influence of temperature, initial Cu(II) ion concentration, and sorbent dosage on the Cu(II) removal from the water matrix using surface-oxidized cellulose nanowhiskers (CNWs) bearing carboxylate functionalities. In addition, this study focused on the actual conditions in a wastewater treatment plant. Conductometric titration of CNWs suspensions showed a surface charge of 54 and 410 mmol/kg for the unmodified and modified CNWs, respectively, which indicated that the modified CNWs provide a relatively high surface area per unit mass than the unmodified CNWs. In addition, the stability of the modified CNWs was tested under different conditions and proved that the functional groups were permanent and not degraded. Response surface methodology (RSM) and artificial neural network (ANN) models were employed in order to optimize the system and to create a predictive model to evaluate the Cu(II) removal performance of the modified CNWs. The performance of the ANN and RSM models were statistically evaluated in terms of the coefficient of determination (R2), absolute average deviation (AAD), and the root mean squared error (RMSE) on predicted experiment outcomes. Moreover, to confirm the model suitability, unseen experiments were conducted for 14 new trials not belonging to the training data set and located both inside and outside of the training set boundaries. Result showed that the ANN model (R2 = 0.9925, AAD = 1.15%, RMSE = 1.66) outperformed the RSM model (R2 = 0.9541, AAD = 7.07%, RMSE = 3.99) in terms of the R2, AAD, and RMSE when predicting the Cu(II) removal and is thus more reliable. The Langmuir and Freundlich isotherm models were applied to the equilibrium data and the results revealed that Langmuir isotherm (R2 = 0.9998) had better correlation than the Freundlich isotherm (R2 = 0.9461). Experimental data were also tested in terms of kinetics studies using pseudo-first order and pseudo-second order kinetic models. The results showed that the pseudo-second-order model accurately described the kinetics of adsorption

Algorithms of automatic enumerating balance of masses of raw coal and the barren rock at driving of the galleries in mining works

W artykule przedstawiono modele matematyczne służące do zautomatyzowania wyliczeń bilansu mas węgla oraz skały płonnej, dla każdego z dni roboczych, składających się na projekt udostępnienia zasobów (wykonania wyrobisk korytarzowych). Rozważono trzy rodzaje algorytmów: dla modelu zakładającego sukcesywne wykonywanie wyrobisk, dla modelu uwzględniającego podział poszczególnych wyrobisk na odcinki różniące się istotnie proporcjami węgla surowego i skały płonnej oraz dla modelu zakładającego równoległe drążenie kilku wyrobisk. Wyliczone funkcje nadają się do bezpośredniego wykorzystania po zdefiniowaniu danych wejściowych.In the article mathematical models being used to automating calculations of balance of masses of raw coal and the barren rock were described, for each of working days comprising for the project of opening deposits (driving of the galleries). Three types of algorithms were considered: for the model assuming the successive performance of excavations, for the model taking into account the division of individual excavations into intervals differing indeed the proportion of raw coal and the waste rock and the model assuming parallel driving a few excavations. Enumerated functions are suitable to direct utilization, after defining entrance data

General method for determining the economic efficiency of mining projects differing in size of investment in technical equipment of mine workings as well as in work progress

W artykule przedstawiono metodę określania granicznych, uzasadnionych ekonomicznie, nakładów inwestycyjnych na wyposażenie techniczne wyrobiska eksploatacyjnego. Jednocześnie założono postęp prac w jednostce czasu oraz graniczny (minimalny) postęp przy określonych nakładach inwestycyjnych przeznaczonych na wyposażenie techniczne. Przyjęto także, że analizę taką prowadzi się, porównując dany projekt testowany z projektem odniesienia. W przeprowadzonych badaniach zastosowano metodę dyskontowanych strumieni pieniężnych. Wartości graniczne wyliczano, zakładając jednakową wartość NPV dla projektów odniesienia i testowanego. Przyjęcie niższych od granicznych nakładów inwestycyjnych powoduje, że projekt testowany daje lepsze efekty ekonomiczne niż projekt odniesienia (także odwrotnie). Podobnie, uzyskanie w projekcie testowanym wyższych wartości postępu prac ponad wartości graniczne, daje lepsze efekty ekonomiczne niż dla projektu odniesienia (także odwrotnie).In the article a method of determining border (maximum), justified economically, of investments on the technical equipment of the exploitation excavation, at established progress of works in the time unit and border (minimal) of progress of works at established investments on this technical equipment was presented. They assumed that such analysis was being conducted comparing the given project tested with the project of reference. A method of discounted cash flows was applied. Enumerated thresholds are on the assumption that for the project of reference and the tested project they are NPV identical. Taking investments lower than border causes, that the tested project is giving better economic effects than the project of reference and on the contrary. Similarly getting maximum values of progress of works in the tested project beyond thresholds is giving better economic effects than for the project of reference and on the contrary 1

Mathematical model for the calculation of the mass of coal and waste rock obtained from exploitation workings under different longwall advances

W artykule przedstawiono model matematyczny służący do zautomatyzowania obliczeń bilansu mas węgla oraz skały płonnej dla każdego z dni roboczych składających się na projekt udostępnienia i wydobycia zasobów. Danymi wejściowymi do tego modelu są: wymiary geometryczne poszczególnych wyrobisk eksploatacyjnych, czas od rozpoczęcia projektu do rozpoczęcia eksploatacji pierwszego wyrobiska, czas przezbrojeń, udział węgla surowego w masie urobku, przeliczniki objętości węgla oraz skały płonnej na ich masę. Zmiennymi sterującymi są postępy dzienne ścian w poszczególnych wyrobiskach. Na wyjściu modelu otrzymuje się masę węgla surowego oraz skały płonnej dla kolejnych dni roboczych projektu. Funkcje modelu same wyliczają czas potrzebny na wyeksploatowanie danego pola oraz budują harmonogram projektu – w zależności od wariantów wartości zmiennych sterujących.The article presents a mathematical model designed for the automation of calculations of the coal and waste rock balance for each of the working days relating to the project of development and exploitation of resources. The input data to this model are: geometric dimensions of individual exploitation workings, time from the start of the project to the beginning of exploitation of the first working, time of rearrangements, shares of raw coal in the mined coal mass, factors of conversion of the volume of coal and waste rock on their mass. Steering variables are longwall daily advances in individual workings. On the outlet of the model one obtains the mass of raw coal and waste rock for successive working days of the project. The model functions calculate the time necessary for the exploitation of the given panel and build the time schedule of the project – according to the variants of the value of steering variables

Method of setting the resultant cutting powers on the head plane coal on the basis of measurements of mechanical parameters of coal

W artykule przedstawiono metodę obliczania wartości wypadkowej siły tnącej na głowicy struga węglowego, niezbędnej do urabiania węgla. Podstawą wyznaczania tej siły są wyniki pomiarów parametrów mechanicznych węgla, wykonywanych specjalnie do tego celu zaprojektowanym przyrządem. Metoda składa się z dwóch etapów: obliczeń teoretycznych oraz określania współczynników dopasowania przybliżających wyniki tych obliczeń do wyników eksploatacji.In the article a method of calculating the resultant cutting powers on the head plane coal was presented, essential to extract coal. Results of measurements of mechanical parameters of coal made on the device especially at this target designed are a ground for appointing this power. This method consists of two stages: of theoretical calculations and determining rates of fitting theoretical calculations giving an approximation of the score to conditions of real exploitations

Free vibration of structures by radial basis function – pseudospectral method

The paper deals with the use of the radial basis function-pseudospectral method in vibration analysis of twodimensional mechanical structures. The method combines meshless features of radial basis function (RBF) with efficiency and simplicity of the pseudospectral method. In present work the main emphasis is laid on appropriate assumption of the interpolant for the sought function due to the number of the boundary conditions in analysed problem. This interpolation function enables to obtain the weighting coefficients for derivative approximation in a governing equation. The method is applied to free vibration analysis of arbitrarily shaped membrane and plate