Recent studies in the area of biological air treatment in filters have addressed fundamental key issues, such as a biofilter bed of different origin composed of natural zeolite granules, foam cubes and wood chips. When foam and zeolite are mixed with wood chips to remove volatile organic compounds from the air, not only biological but also adsorption air purification methods are accomplished. The use of complex purification technologies helps to improve the efficiency of a filter as well as the bed service life of the filter bed. Investigations revealed that microorganisms prevailing in biological purification, can also reproduce themselves in biofilter beds of inorganic and synthetic origin composed of natural zeolite and foam. By cultivating associations of spontaneous microorganisms in the filter bed the dependencies of the purification efficiency of filter on the origin, concentration and filtration time of injected pollutants were determined. The highest purification efficiency was obtained when air polluted with acetone vapour was supplied to the equipment at 0.1 m/s of superficial gas velocity. When cleaning air from volatile organic compounds (acetone, toluene and butanol), under the initial pollutant concentration of ~100 mg/m3, the filter efficiency reached 95 %.
The energy industry is undergoing a major upheaval. In Germany, for example, the large nuclear and coal-fired power plants in the gigawatt scale are planned to be shut down in the forthcoming years. Electricity is to be generated in many small units in a decentralized, renewable and environmentally friendly manner. The large 1000 MW multistage axial steam turbines used to this date are no longer suitable for these tasks. For this reason, the authors examine turbine architectures that are known per se but have fallen into oblivion due to their inferior efficiency and upcoming electric drives about 100 year ago. However, these uncommon turbine concepts could be suitable for small to micro scale distributed power plants using thermodynamic cycles, which use for example geothermal wells or waste heat from industry to generate electricity close to the consumers. Thus, the paper describes and discusses the concept of a velocity-compounded single wheel re-entry cantilever turbine in comparison with other turbine concepts, especially other velocity-compounded turbines like the Curtis-type. Furthermore, the authors describe the design considerations, which led to a specific design of a 5 kW air turbine demonstrator, which was later manufactured and investigated. Finally, first numerical as well as experimental results are presented, compared and critically discussed with regards to the originally defined design approach.
The objective of the study was to compare the impact of three systems of multiannual fertilization applied in two long-term field experiments on the content of phenolic compounds in the soil. In the study, both natural (manure, slurry) and mineral (NPK) fertilizers were used, along with combined, organic-and-mineral fertilization. Experiment I was established in 1972 on grey brown podzolic soil; experiment II, in 1973 on brown soil. In both experiments crops were cultivated in a 7-year rotation, with a 75% share of cereals. The experimental samples were taken from the top layer of soil after 36 (experiment I) and 35 (experiment II) years following the establishment of the experiments. It was demonstrated that the presence of phenolic compounds in the soils was significantly dependent on the contents of organic C and total N, type of soil and the type and dose of used fertilizers. In grey brown podzolic soil, the content of total phenolic compounds was at a lower level than the content found in brown soil. Multiannual fertilization contributed to an increase in the content of total phenolic compounds in relation to the values obtained in control objects, which was particularly reflected in the soil originating from objects fertilized with slurry applied at a dose being equivalent to manure in terms of the amount of introduced organic carbon. The percentage of water-soluble phenols in the total content of these compounds in grey brown podzolic soil was at the level of 18.4%, while in brown soil it amounted to 29.1%.
Allelopathy is a complex phenomenon which depends on allelochemical concentrations. So, two pot experiments were carried out to investigate the allelopathic effect of alcoholic fresh shoot extract of Eruca sativa (foliar spray) and E. sativa shoot powder (mixed with soil) on Pisum sativum plants and two associated weeds, Phalaris minor and Beta vulgaris. The experiments were conducted in the greenhouse of the National Research Centre, Giza, Egypt during two successive winter seasons (2016–2017 and 2017–2018). Ten treatments were applied in this study. Four treatments were applied before sowing, that E. sativa shoot powder was mixed with the soil at rates of 15, 30, 45 and 60 g ⋅ pot–1. The other four treatments of E. sativa alcoholic fresh shoot extract were sprayed twice on both plants and weeds at 5, 10, 15 and 20% (w/v) concentrations. Additionally, two untreated treatments, healthy (P. sativum only) and unweeded (untreated infested P. sativum plants with weeds) were applied for comparison. The results indicated that both alcoholic extracts and powder reduced growth of both weeds. Moreover, there was a direct relationship between concentration and weed reduction. Eruca sativa alcoholic extracts increased yield parameters of P. sativum plants. The maximum yield attributes were recorded by spraying of E. sativa alcoholic extract at 20%. On the other hand, it was clearly noticed that the high powder rates affected negatively P. sativum yield parameters. But the lowest powder rate (15 g ⋅ pot–1) stimulated P. sativum yield parameters as compared to unweeded treatment. Chemical analysis of E. sativa shoot powder ensured that the abundant amount of glucosinolates (9.6 μmol ⋅ g–1) and phenolic compounds (46.5 mg ⋅ g–1) may be responsible for its allelopathic effect. In conclusion, spraying of alcoholic fresh shoot extract of E. sativa at 20% (w/v) and mixing E. sativa shoot powder at 15 g · pot–1can be applied as natural bioherbicides for controlling weeds.
The paper presents investigation results of the migration of a chemical compound contained in fly ash deposited on a dry furnace waste landfill site exposed to weather conditions. Climate conditions are able to significantly affect chemical component distribution in a block of deposited, moving chemical compounds to different depths. The main aim of the investigations was to determine the chemical component distribution of deposited fly ash in the landfill. Identification of chemical components based on XRF analysis indicated the existence of differences in both tested storage layer and the fraction of fly ash.
The gas porosity is one of the most serious problems in the casting of aluminum. There are several degassing methods that have been
studied. During smelting of aluminum, the intermetallic compound (IMC) may be formed at the interface between molten aluminum and
solid steel of crucible furnace lining. In this study, the effect of degassing treatment on the formations of IMC has been investigated. The
rectangular substrate specimens were immersed in a molten aluminum bath. The holding times of the substrate immersions were in the
range from 300 s to 1500 s. Two degassing treatments, argon degassing and hexachloroethane tablet degassing, were conducted to
investigate their effect on the IMC formation. The IMC was examined under scanning electron microscope with EDX attachment. The
thickness of the IMC layer increased with increasing immersion time for all treatments. Due to the high content of hydrogen, substrate
specimens immersed in molten aluminum without degasser had IMC layer which was thicker than others. Argon degassing treatment was
more effective than tablet degassing to reduce the IMC growth. Furthermore, the hard and brittle phase of IMC, FeAl3, was formed
dominantly in specimens immersed for 900 s without degasser while in argon and tablet degasser specimens, it was formed partially.
In the morphosyntactic literature, there exist two approaches to the problem of argument structure in English nominal synthetic compounds such as furniture moving or dog training. According to Borer (2012), such synthetic compounds belong to the class of referential nominals and thus lack argument structure. On the other hand, Alexiadou (2017) maintains that the external argument is present in the structure of synthetic compounds due to their ability to co-occur with by-phrases. In this paper, we present an extensive set of corpus data to show that synthetic -ing compounds do project the external argument, which is evidenced by their ability to license not only by-phrases but also agent-oriented adjectives and instrumental phrases. Importantly, the corpus data indicates that certain synthetic -ing compounds display the capacity to occur in aspectual contexts; nominal compounds fall in two classes in that regard.
Research on the chemistry of atmospheric precipitation in the Hornsund region of Svalbard has been extended by analysis of the organic contents. In rainfall samples collected in September 2003, the organics were separated by solid phase extraction (SPE), eluted and analysed on gas chromatograph coupled to a mass selective detector (GC/MS). Rainfall pH was in the range 4.72–5.45, the low values suggesting possible pollution. Concentrations of inorganic ions, expressed as total dissolved salts (TDS), were 5.40–13.18 mg L–1. Non-sea-salt (nss) sulphates were in the range 5–11 μeq L–1. In all samples, long-chain alkanes with chain length up to C36, and their methyl derivatives were detected. Among aromatic compounds biphenyl, dibenzofuran and its methyl derivatives were found. Polycyclic aromatic hydrocarbons (PAHs) were represented by naphthalene, phenanthrene, fluorene, acenaphthene, fluoranthene and pyrene. There were no PAHs with higher numbers of rings. The synoptic meteorological conditions in September 2003 indicate that all organic and inorganic pollutants were of local origin.
In this paper, of primary interest is to synthesis 8-(1H-indol-3-ylazo)-naphthalene-2-sulfonic acid (INSA) and to evaluate the main parameters of Au/INSA/n-Si/Al diode in dark and under illumination. Different techniques are used for interpreting the proposed INSA chemical structure. The dark current-voltage measurements were achieved in the temperature range of 293−413 K. It is noticed that INSA films modify the interfacial barrier height of classical Au/n-Si junction. At low applied voltages, the I–V relation shows exponential behavior. The values ideality factor, n, and the barrier height, φ, are improved by heating. The abnormal trend of n and φ is discussed, and a homogenous barrier height of 1.45 eV is evaluated. The series resistance is also calculated using Norde's function and it changes inversely with temperature. The space charge limited current ruled with exponential trap distribution dominates at relatively high potentials, trap concentration and carriers mobility are extracted. The reverse current of the diode has illumination intensity dependence with a good photosensitivity indicating that the device is promising for photodiode applications.
A laboratory study was performed to study the effects of various operating factors, viz. adsorbent dose, contact time, solution pH, stirring speed, initial concentration and temperature on the adsorption of triphenyltin chloride (TPT) onto coal fly ash supported nZnO (CFAZ). The adsorption capacity increases with increase in the adsorbent amount, contact time, pH, stirring speed and initial TPT concentration, and decrease with increase in the solution temperature. The adsorption data have been analyzed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) adsorption models to determine the mechanistic parameters associated with the adsorption process while the kinetic data were analyzed by pseudo first-order, pseudo second-order, Elovich, fractional power and intraparticle diffusivity kinetic models. The thermodynamic parameters of the process were also determined. The results of this study show that 0.5 g of CFAZ was able to remove up to 99.60% of TPT from contaminated natural seawater at 60 min contact time, stirring speed of 200 rpm and at a pH of 8. It was also found that the equilibrium and kinetic data fitted better to Freundlich and pseudo second-order models, respectively. It can therefore be concluded that CFAZ can be effectively used for shipyard process wastewater treatment
The aim of this study was to determine the impact of the temperature of wastewater in a biological reactor with activated sludge and the BOD5/N-NH4 ratio in the influent to the treatment plant on nitrification efficiency and the concentration of ammonium nitrogen in treated wastewater. Tests were carried out in a household wastewater treatment plant which collects and treats sewage from a school building and a teacher’s house. During the 3-year study, large fluctuations in the sewage temperature in bioreactor were noted which was closely related to the ambient temperature. There were also large fluctuations in the concentration of organic matter and the concentration of ammonium nitrogen in inflowing sewage. The influence of wastewater temperature in the bioreactor and the BOD5/N-NH4 ratio on the concentration of ammonium nitrogen in treated wastewater was determined using Pearson’s linear correlation. A statistical analysis showed that a 1°C decrease in the temperature of wastewater in the bioreactor increased the concentration of ammonium nitrogen in treated wastewater by 2.64 mgN-NH4·L-1. Moreover, it was found that nitrification depended on the ratio of BOD5 to the concentration of ammonium nitrogen in wastewater flowing into the bioreactor. An increase in the BOD5/N-NH4 ratio by 1 value led to a 5.41 mgN-NH4·L-1 decrease in the concentration of ammonium nitrogen.
In the present study, the novel quaternary ammonium salt (QAS+), 1-methyl-di-octyl-1 phenyl ammonium iodide (QAS1), was synthesized by complete alkylation reaction. Sodium montmorillonite (Mt) was modified via an ion-exchange reaction with QAS1+. The modified material and quarternary ammonium salt (Mt1 and QAS1) were analyzed by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Removal capacity of hydrophobic organic pollutants such as 4-nitrophenol (4-NP) and 2,4-dinitrophenol (2,4-DNP) from solution media of synthesized organoclay was evaluated. The optimum conditions and batch kinetics of adsorption of 4-nitrophenol and 2,4-dinitrophenol from aqueous solutions are reported. It was shown that the adsorption capacity decreased in the order 4-NP> 2,4-DNP. The total mass loss during the drying process was 66% and 78%, respectively. Thermodynamic parameters enthalpy (∆H0) and entropy (∆S0) and the mean free energy (E) for the adsorption of nitrophenol compounds (NCP) were determined.