The influence of sorption processes on gas stresses leading to the coal and gas outburst in the laboratory conditions

The seepage of gas through coal and in particular through coal briquettes has already been a quite well known phenomenon. This also refers to its influence on certain initial conditions of coal and gas outbursts such as threshold values of so called gas stresses. In turn a detailed research on the influence of sorption processes on these conditions has been neglected until now. There is, however, an opinion that (fast) desorption is crucial for rock and gas outburst initiation and continuance, although many examples contradict such a thesis. The goal of the studies described here was to investigate a part of this ambiguity, namely the influence of sorption processes on gas stresses leading to coal and gas outbursts carried out in laboratory conditions.A series of laboratory experiments concerning provoking coal and gas outbursts was conducted. Coal briquettes and two gases: nitrogen and carbon dioxide were used. The experimental data was computed out into the gas stresses and the most important information was extracted. The obtained results showed that in experiments with nitrogen slightly higher gas stresses and thus more intensive provoking were needed in order to initiate outburst than in experiments with carbon dioxide. It indicates that sorption may be the factor that promotes outbursts. Comparative analysis implied also that for a given level of gas stresses the more sorptive the gas was, the longer it took to initiate an outburst. Moreover, in the experiments with nitrogen the global maximum of gas stresses occurred deeper inside of the briquette for any given time than in experiments with carbon dioxide. All the found differences were weak, though easily noticeable.     

Dynamic compensation of load cell response: A time-varying approach

This paper presents a new method for dynamic compensation of the load cell response using linear time-varying continuous-time filter. Load cells have an oscillatory response which always needs time to settle down. Therefore, it is justified to search a technique for an effective improvement of the sensor response. The paper describes a theoretical implementation of the proposed time-varying filter, and suggests the implementation technique with the aid of which this kind of filter can be implemented in practice. Simulation results verifying the effectiveness of the proposed filter are presented and compared to the traditional time-invariant configuration.     

Local balance-based adaptive control in the heat distribution system – Practical validation

This paper presents the experiences from the practical implementation and the results of the experimental validation of the balance-based adaptive control (B-BAC) methodology in the application to two local control problems in the simple heat distribution system: the control of the outlet temperature for the electric flow heater and the control of a fluid flow process through the equal percentage valve. Evaluation criteria include measure of the control variable performance as well as the manipulated variable action. The results illustrate both the possibility of the practical implementation of the B-BAC methodology and the fact that in some cases this methodology ensures better disturbance rejection with the tracking properties comparable to the conventional PI controller.     

Changes in activity during storage and characteristics of superoxide dismutase from hen eggs (<Emphasis Type="Italic">Gallus gallus domesticus</Emphasis>)

Hen eggs are one of the most popular food stuffs. Moreover, they can be the source of not only nutrients but also factors of biological origin, which may be used for food preservation and food additives. The aim of the study was to determine and describe the activity of superoxide dismutase isoforms (SOD; EC 1.15.1.1) in hen eggs (Gallus gallus domesticus). Our electrophoretic studies confirmed the presence of SOD isoenzyme bands with molecular weight of 14–15 and 50–70 kDa in egg yolk. By contrast, in egg white, we confirmed the presence of a protein with molecular weight of 13–14 and 50–55 kDa. Zymografic pattern confirmed the activity of SOD isoforms of the enzyme present in the egg yolk; however, it did not confirm enzyme activity in egg white (at the level of error of the used method). Study has also shown SOD activity during storage at 4 °C for 9 days in egg yolk and egg white. In start time, SOD activity in egg yolk is clearly different from a small activity in the protein (respectively, 90.5 ± 22.2 and 7.9 ± 3.9 U g⁻¹). It did not change during 6 days storage but between 6th and 9th day, it decreased significantly in egg yolk while remained low but unchanged in egg white. Present study confirmed the presence of SOD and its activity in hen egg yolk.     

Ozonation within an Activated Sludge System for Azo Dye Removal by Partial Oxidation and Biodegradation

Pre-ozonation is often uneconomical for typical wastewaters with varied mixtures of organic compounds as more biodegradables than non-biodegradables are oxidized, all requiring ozone. The concept developed in this paper is ozonation within an activated sludge system to oxidize recalcitrant substances to more degradable forms and byproducts and to immediately assimilate or biodegrade these within the biological system. The focus was on a novel method of combining ozonation and biological treatment in one integrated unit without adversely affecting the bacterial population responsible for the biological degradation. An azo dye, spiked into the wastewater feed was used to study removal of a recalcitrant compound in a biological system.     

Heat transfer in the thermal entrance region for drag reduction surfactant solutions in pipe flow

Experimental results relating to heat transfer for a flow of surfactant solutions in the thermal entrance region of a pipe were discussed. Aqueous solutions of hexadecyltrimethylammonium chloride with addition of sodium salicylate were used as model fluids. It was observed that the effect of buoyancy on the heat transfer process was less pronounced in the entrance region of a pipe than in the scope of a fully developed flow. It was demonstrated that it was possible to correlate experimental results for the flow of drag-reducing surfactant solutions, based on the dependence of Nusselt number on a dimensionless longitudinal coordinate. In addition, simple empirical equations were proposed which enable the local and mean values of the heat transfer coefficient to be calculated.     

Evaluation of the amino acid content and the quality of protein in florets of white cauliflower: raw, cooked, and prepared for consumption after freezing

The aim of the work was to evaluate the retention of amino acids in white cauliflower florets and the quality of protein. The investigation concerned the raw material and florets prepared for consumption, both from the fresh material and from two types of frozen product: one obtained using the traditional method (blanching–freezing–refrigerated storage–cooking); and the other using a modified method (cooking–freezing–refrigerated storage–microwave defrosting and heating). In 100 g of the raw material the total amino acid content was 1674 mg; the content was significantly higher only in the modified frozen product. The amino acid content found in 16 g N did not significantly differ between the investigated samples, varying in the range of 79.76–87.53 g. Essential amino acids constituted 43–45%. In all the samples the limiting amino acids were cystine with methionine, with glutamic and aspartic acids dominating.     

Trends in NOx abatement: A review

Implementation of stringent regulations of NO_x emission requires the development of new technologies for NO_x removal from exhaust gases. This article summarizes current state of NO_x abatement strategy. Firstly, the influence of NO_x on environment and human health is described. The main focus is put on NO_x control methods applied in combustion of fossil fuels in power stations and mobile vehicles, as well as methods used in chemical industry. Furthermore the implementation of ozone and other oxidizing agents in NO_x oxidation is emphasized.