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During the dewatering process, centrate is produced, which is returned to the beginning of the technological system. The quality of the resulting centrate, and therefore the size of the returned load of pollutants, affects the demand for electricity in the process of biological wastewater treatment. The following study presents the results of centrate quality tests at five wastewater treatment plants located in Poland. The dependence between suspended solids content and ammonia and COD concentrations in the centrate was determined. It was estimated that an increase in the overall suspended solids leads to an increase in COD by about 1.15 kgCOD/kgTSS. No correlation was found between TSS concentration and ammonia. It was calculated that the complete elimination of suspended solids from the sludge would reduce the electricity consumption for all five objects by about 535 MWh/y.

Purifying air from dust is a very important, current topic. There are many methods to minimize the amount of dust, one of them being chamber filters. This paper presents the research results of a newly designed rectangular chamber filter. The efficiency of the dedusting process is influenced by contamination properties, but also by the construction of the apparatus, inlet, and outlet location, the ratio of certain dimensions, and the gas flow rate. The airflow containing solid particles is a multi-phase, difficult-to-describe issue, therefore an attempt to determine the trajectory of particle movement in the apparatus was carried out using the PIV method. A decrease in the dedusting efficiency was observed with the increase of the gas flow rate, as well as for smaller diameters of the solid particles. The obtained values of the efficiency of the apparatus are comparable with the values obtained for the constructions discussed in other papers.

The aim of the study was to relate the influence of the chemical composition, structure, and basic properties as hardness of the tested drill bits on resistance to their wear. The chemical composition of the drill bit was investigated using the electric excitation emission spectrometry method and EDS microanalysis. Metallographic specimens were prepared and observed to determine the structure of each tool. Hardness tests were carried out on the shank and the working part of the tools. Material wear tests were carried out on the basis of measuring the wear of the drill bit flank. It has been shown that the appropriate selection of the chemical composition and heat treatment has a significant impact on the wear resistance of cutting tools, which directly translates into their quality.

This paper summarises a series of large-scale fire suppression tests conducted to simulate a fire in the big surface and/or surface sprinkling. The subject of this paper is the research on water spraying with the use of the Turbo Jet 2011 water-foam nozzle manufactured by Supon Białystok. The results discuss the pressure losses caused by the flow through the discharge hose, spray angle, and the intensity of surface sprinkling. The greatest stream ranges and the highest maximum values of the sprinkling intensity were obtained at the capacity of 400 l/min, and a solid spray angle. The smallest values were obtained at 200 l/min, a pressure of 5 bar, and a solid spray angle. The actual pressures taking into account the losses in the hose section were calculated. As for the highest firefighting effectiveness of the stream, the authors recommended the following parameters: semi spray angle, 200 l/min, and 2.5 bar.

In this paper, particular attention is paid to an advanced variant of the plug-in hybrid electric vehicle, known as PHEV, which combines two functionalities: the vehicle's internal combustion engine (ICE) and the electric motor. The study described herein also presents the influence of factors such as the ambient temperature, vehicle speed and traffic distance on the PHEV's energy consumption. It has been shown that the vehicle's range estimated based on its electronic control module (ECU) is about 20% shorter per annum on average for its year-round operation in everyday driving conditions. When analyzing the energy consumption based on the vehicle's unitary energy consumption model, attention was paid to values that are strongly correlated with traffic and weather conditions. In addition, the authors emphasized that the estimated total energy consumption of a battery electric vehicle (BEV) or hybrid vehicle (PHEV), relative to the normative values arising from the type approval test cycle, deviate from the actual values arising from real driving conditions and often vary substantially. As shown in this paper, the energy consumption intensity of a vehicle is significantly influenced not only by its speed but also by weather conditions, including ambient temperature. In extreme cases, energy consumption intensity can increase by up to 68% relative to a WLTP (Worldwide Harmonized Light Vehicle Test Procedure) cycle. [ABSTRACT FROM AUTHOR]

The review presents the D2-law of droplet evaporation, which is used to describe the spraying process involving the evaporation of droplets. This law, the subject of numerous publications, can be successfully applied to describe the droplet evaporation process under various conditions, including the calculations of the process of feeding the boiler with a liquid that contains catalyst particles. To date, not a lot of work has been devoted to this issue. The paper is a continuation of previous research concerning the spraying of liquids with a catalyst, which improves the efficiency of the process. The conducted analysis showed that the experimental data from previously published work are very compatible with the data obtained from the D2-law of droplet evaporation. At the standard speed of about 20 m/s of an aerosol flowing through a dust duct, droplets in the stream should be observed up to a distance of 1 m from the outlet of the apparatus supplying the system. Under such flow conditions, a droplet's lifetime must be above 0.05 s. The dependence between a droplet's lifetime and its diameter and temperature was determined. The obtained results confirmed that the effective droplet diameter is above 30 µm. Such droplets must be generated and then fed to the boiler for the catalyst to work properly. This law is an engineering approach to the problem, which uses relatively simple model equations in order to determine the evaporation time of a droplet. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental studies on one- and two-phase flow in packed columns. In the study, natural materials (LECA, pumice stone, cones, coconut fiber, wood chips, walnuts, shells), waste materials (plastic nuts, bricks, tiles), copper springs, and plastic acorns were used as packing. The relationship between the flow resistance coefficient and the Reynolds number is described. In the model, the relationship between the pressure drop on the sprayed packing and the pressure drop on the dry packing is presented. The characteristic values for the studied materials were obtained. The study constitutes the basis for further studies of packings of various origins in order to determine the influence of variable geometrical dimensions. [ABSTRACT FROM AUTHOR]