Most of the Indian cities and towns have been facing serious traffic noise pollution due to urbanization, substantial growth of new vehicles, inadequate road network, etc. Automotive traffic, railroads, and air traffic are the most common sources of noise pollution in cities, with vehicular traffic accounting for around 55% of overall metropolitan noise. Prolonged exposure to such loud noise causes anger, stress, mental diseases, discomfort, hypertension, concentration problems, and sleeplessness. This study aims to investigate the effects of COVID-19 societal lockdown on changes in the noise pollution levels before, during, and after the lockdown period in various industrial, commercial, residential, and silence zones in Bengaluru, India, in light of the recent imposition of COVID-19 societal lockdown. According to data acquired from the KSPCB (Karnataka State Pollution Control Board) online portal, the average noise levels before and during lockdown were determined to be in the range of 59.4 dB to 70.9 dB and 58.2 dB to 62.7 dB for different zones. During the lockdown, all commercial, industrial and educational activities were closed to limit the spread of infection, resulting in usage of private and commercial transportation declining dramatically. Reduction in the noise level was observed during the lockdown in all monitoring stations of Bengaluru, except for Indira Gandhi Institute of Child Health, where the noise level didn’t decline because of a COVID emergency. Maximum reduction was observed in the commercial area (11.56%) followed by industrial areas (8.34%). The result further indicated that only the industrial area experienced an increase of 8.41% in noise level, while other areas experienced a reduction in a noise level during the early post-lockdown. During the mid and late post-lockdown periods, most locations experienced a rapid spike in the noise intensity.

The possibilities to improve values of the satellite orbit elements by employing the pseudo-ranges and differences of carrier phase frequencies measured at many reference GPS stations are analysed. An improvement of orbit ephemeris is achieved by solving an equation system of corrections of the pseudo-ranges and phase differences with the least-squares method. Also, equations of space coordinates of satellite orbit points expressed by ephemeris at fixed moments are used. The relation between the accuracy of the pseudo-ranges and phase differences and the accuracy of the satellite ephemeris is analysed. Formulae for estimation of the influence of the ephemeris on the measured pseudo-ranges and phase differences and for prediction of the accuracy of the pseudo-ranges and phase differences were obtained. An influence of the covariance between single orbit parameters on the accuracy of the pseudo-ranges and phase differences is detected.

Wood pellets are classified as a solid biomass type. They are one of the most popular bio-heating fuels used in Europe, especially in the small heating sector, where pellets are burned in low-power domestic boilers. The pellets and automatic pellet-fired heating devices gained popularity due to the increasing air pollution (smog) problem and the low emission limiting campaigns associated with it. Wood pellets are formed as a result of small forestry particles mechanical compression (mainly conifers originated) and they are listed among renewable energy sources. The purpose of the presented studies was to compare the quality of wood pellets used for pellet-fired boilers and to identify, qualitatively and quantitatively, impurities marked in the samples obtained from the domestic market. The application of petrographic analyses, applied so far in relation to fossil fuels, is a presented work innovation for wood pellets. The microscopic analyses were performed on both certified (ENplus/DINplus) and uncertified wood pellets available on the market. Unfortunately, the analysis revealed that the quality requirements were not met, because of the unacceptable contamination presence. The unacceptable organic inclusions in the analyzed samples are fossil coals and their derivatives, coke, and polymeric materials of natural origin. Unacceptable inorganic inclusions determined in the analyzed samples were: glass, slag, rust, pieces of metal, stone powder, plastic, and polymeric materials of inorganic origin.

The research issues discussed in the paper concentrate on the participation of the municipal services sector in shaping local development in the commune. The aim of the study is to verify the actual level of involvement of this sector in the development process of the commune, and the thesis is: “The activities of the municipal services sector are one of the factors shaping local development in the commune.” The basic research method is a critical review of domestic and foreign literature and participant observation.

The article focuses on multicomponent system separation with the use of an innovative membrane-based technique i.e. pervaporation. Pervaporation is a membrane technique for separation of liquid mixtures on solid nonporous membranes. Pervaporation is used in this study to separate a quaternary system acetone-butanol-ethanol-water. Such a system may be derived from ABE fermentation process, and the resulting product, biobutanol, is a potential biofuel and may be used in internal combustion engines.

Experiments in the study involving concentration of butanol by pervaporation were performed using PERVAP 4060 flat-sheet commercial membrane. To describe the PV process a semi-empirical approach was used. As a result of experiments and calculations permeance coefficients were obtained. Separation and permeance factors were calculated to assess the efficiency of the system separation. Beforehand, activity coefficients were determined for all the components of the mixture with the NRTL equation. Separation coefficients for all the components differed depending on process parameters: concentration, feed flow rate and process temperature. The study confirmed the separation effect of the quaternary system. The most interesting results were obtained for the concentration of butanol. Pervaporation allows to concentrate butanol over 10 times. The permeance coefficient reached for butanol an average value of 7.06·10-3 in comparison with the results for ethanol 3.24·10-2 and acetone 1.83·10-2 [kmol(m2h)-1]. The temperature change from 50 to 70°C led to an increased permeance factor and there was no apparent effect on it in the feed flow rate. Due to the hydrophobicity of the membrane water fluxes in the quaternary system were negative.