Tons Of Dust Research Articles

The importance of forests in the environment

The importance of forests in the environment

Scientific and technical problems of transition from open pit to combined technologies for raw materials mining

In Kryvyi Rih iron ore basin, long-term and intensive mining of deposits applying open pit methods have resulted in significant areas disturbed by open pits, dumps and tailings storage facilities. Hundreds of thousands of hectares of fertile arable land are already unsuitable for agriculture and sometimes for living. Thousands of tonnes of dust from dumps and tailing ponds deteriorate the surrounding nature every year and pollute the atmosphere in mining basins. Industrial ore breaking in open pits using bulk blasting causes emissions of a significant amount of harmful dust and carcinogenic substances. The environmental situation in open pit mining areas is often close to critical. In addition, bulk blasting forms a seismic wave, which in some cases destruct civil buildings and industrial facilities. The article proposes ways of gradual transition from mining mineral deposits by open pit methods to environmentally friendly technologies of open pit-underground and underground mining. It is established that such transition is a forced and at the same time choiceless way of developing mining areas, in particular Kryvyi Rih iron ore basin. The paper notes that the main problems of this transition include geomechanical stabilization of the rock massif during construction of underground mines in areas of possible impacts of open pit fields. The paper develops the fundamental study of the problems of controlling the stress-strain state of the massif during transition from the open pit to combined technology of deposit mining. Technologies of combined mining that involve formation of a transition belt with backfilling the worked-out space with compound mixtures are studied as well. It is proved that development of theoretical foundations for controlling the stress-strain state of the massif during transition from the open-pit to combined technology of deposit mining, study and design of technological solutions that contribute to transition to open pit-underground and underground mining, is an urgent scientific, technical and practical problem of great importance.

Long-term study of desert dust deposition effects on phytoplankton biomass in the Persian Gulf using Google Earth Engine

Persian Gulf is surrounded by the most active dust source regions of the world. Every year, millions of tons of dust are deposited in this area causing significant adverse effects. This research aimed to fill the gap in the field of dust impact quantification regarding different and important regions in the Persian Gulf. We evaluated aerosol optical thickness (AOT) as dust, chlorophyll a (Chl a) as phytoplankton biomass, sea surface temperature (SST), and particulate organic carbon (POC) using Moderate Resolution Imaging Spectroradiometer (MODIS) data to quantify and analyze the impacts of dust. According to dust frequency maps over 21 years, 4 critical regions were selected including the Northern, Central, and Southern regions of the Persian Gulf and Strait of Hormuz. Slightly lower Chl a values were noted in the southern region and Strait of Hormuz compared to the Northern and Central regions. The Mann-Kendall (MK) test and Sen's slope estimator, which can determine trend parameters, were used to analyze 4 selected regions using 8 days, monthly, and yearly averaged data. The results of the MK test showed a significant positive trend for SST and a significant negative trend for POC. AOT and Chl a trends varied based on their locations. The cross-correlation test with a time lag showed maximum correlations between Chl a and dust (AOT) with a delay of 6–7 months. Also, to quantify the impacts of dust on phytoplankton biomass, R2 and analysis of variance (ANOVA) regression were used for data with a 6–7-month time lag. The results showed that the contribution of dust in the amount of Chl a variation was about 10 %–20 %. This study showed that the simultaneous use of remote sensing and statistical methods could provide necessary and timely warnings (regarding management) to prevent algal blooms and aquatic loss in this important and strategic area.

Manufacturing, curing and mechanical testing of BREX from electric arc furnace dust

At present the acute issue is utilization and recycling of metallurgical production wastes; one of which is electric arc steelmaking dust (EAF). In Russia there are up to 30 million tons of dust in the dumps of metallurgical plants and additionally up to 780 thousand tons are added to this amount annually. Considering the amount, the main value is zinc, which content reaches 25 wt%, as well as iron, which content varies from 20 to 50 wt%. The paper presents the results of studies on briquetting of the EAF dust using the technology of stiff extrusion and obtaining brackets. The chemical composition of the initial EAF dust was studied by X-ray spectral analysis using JEOL JSM-7001F electron microscope. The amount of reducing agent was selected based on results of thermodynamic modeling using the TERRA software package. The BREX were produced in a laboratory extruder assembled from an electric motor, a reduction gear, a screw, and a die. Two types of dies were used in the briquetting study. For each type the optimum moisture and binder were selected. The influence of the binder and moisture on the quality of the finished briquettes was evaluated. The BREX drying was studied in order to find out the optimum curing time in the air. In addition, drying at 110 °C was carried out for a comparative assessment of the strength of briquettes depending on the method of drying. The drop tests of the finished briquettes were carried out according to GOST 25471‒82 “Iron ores, sinter and pellets; method for determining dumping strength”. The test results showed the possibility of transportation of the EAF dust briquettes

Characteristics of Cancers in Community Members Exposed to the World Trade Center Disaster at a Young Age.

The destruction of the World Trade Center (WTC) towers on 11 September 2001 (9/11) released tons of dust and smoke into the atmosphere, exposing hundreds of thousands of community members (survivors) and responders to carcinogens. The WTC Environmental Health Center (WTC EHC) is a federally designated surveillance and treatment program for community members who were present in the New York City disaster area on 9/11 or during the months that followed. WTC EHC enrollment requires exposure to the WTC dust and fumes and a federally certifiable medical condition, which includes most solid and blood cancers. Several studies have described the prevalence and characteristics of cancers in responders and survivors exposed to the WTC dust and fumes as adults. Cancers in those exposed at a young age warrant specific investigation since environmental toxin exposure at a younger age may change cancer risk. We describe the characteristics of 269 cancer patients with 278 cancer diagnoses among WTC EHC enrollees who were young in age (aged 0 to 30) on 9/11. These include 215 patients with a solid tumor (79.9%) and 54 with a lymphoid and/or hematopoietic cancer (20.1%). Among them, 9 patients had a known second primary cancer. A total of 23 different types of cancer were identified, including cancer types rare for this age group. Many were diagnosed in individuals lacking traditional cancer-specific risk factors such as tobacco use. The current study is the first to report specifically on cancer characteristics of younger enrollees in the WTC EHC program.

Coupled Thermodynamics and Phase Diagram Analysis of Gas-Duct Concretion Formation in Pyro-Processing Ironmaking and Steelmaking Dust

In recent years, the steel industry has accumulated approximately 100 million tons of dust annually, severely threatening the environment. Rotary kiln technology is one of the main industrial methods used to process this dust. However, some substances in flue gas congeal on the cooling wall of the gas duct and seriously affect production. In this study, the properties and formation mechanisms of the coagulum were investigated on the basis of experimental and thermodynamic analyses. The experimental results showed that the coagulum is mainly composed of chlorides (KCl, NaCl, and ZnCl2), oxides (ZnO, FeO), and carbon, with three structures: lumps, fibers, and particles. Based on a thermodynamic analysis, a reasonable explanation was proposed to clarify the formation mechanism. The liquid phase (a eutectic system of KCl–NaCl–ZnCl2), dendrites (KCl, NaCl), and particles (ZnO, FeO, C) were found to act as binders, stiffeners, and aggregates in the coagulum, respectively, constituting a composite structure. Liquids acting as binders are essential for coagulum formation, and dendrites and particles strengthen this effect. Furthermore, the eutectic system of chlorides plays a crucial role in coagulum formation. The results of the present study offer a theoretical understanding of gas-duct coagulation and will provide guidance for adopting alleviation measures.

Study on air pollution control under the influence of energy policy in Shanxi Province

At present, China’s resource constraints are becoming tighter and environmental problems are serious. Shanxi province’s energy policies implementation has a huge impact on the ecological environment. This paper focuses on the emission of air pollutants from coal-fired power generation, coal chemical industry, biomass power generation, coal bed methane power generation, as well as the impact of emission reduction measures such as "coal to electricity" and "coal to gas" on the atmospheric environment in Shanxi Province. In 2015, coal power, coal chemical and other energy-related industries in Shanxi province emitted 429,800 tons of sulfur dioxide, 348,000 tons of nitrogen oxides and 364,400 tons of dust, accounting for 38%, 37% and 25% of the province’s industrial emissions respectively. After the strict implementation of energy policies, the emissions of air pollutants SO2, NOx and dust from energy-related industries should be 121,500 tons, 236,100 tons and 19,300 tons respectively in 2020. Emission of air pollutants SO2, NOx and dust from energy-related industries should be reduced by 72%, 32% and 95% respectively in 2020 compared with that of 2015. However, we need to improve environmental access, tighten standards, strengthen environmental protection requirements in the energy industry, and continue to optimize the energy consumption structure.

Man-made pollution of the environment with coal dust as a result of operation and closure of coal mines

The technological processes of coal mining, enrichment and use, in particular coal combusting is accompanied by formation and release of significant amounts of dust and gases. Atmospheric air protection is one of the most urgent problems of the nowadays technological society, as scientific and technological progress and expansion of production is associated with an increase in negative anthropogenic impacts on the atmosphere. The paper presents a new solution to the current scientific problem of reducing carbon-containing dust content based on the disclosure of the laws of the aerodynamic interaction of dust and water flows in gravitational and electrostatic fields. The authors show in this study the causes of atmosphere pollution with coal-containing dust; main issues of atmospheric air protection at enterprises located in the controlled territory of Ukraine. The data of the first quarter of the 2020 year are presented in the research. The biggest part of the facilities that pollute the atmospheric air are focused in Donetsk and Lugansk regions. It is estimated that the air environment of the underground mine surface complex is filled with exhaust ventilation air of approximately 200.000 m3 per minute with a dust concentration of approximately (5-7) mg / m3, which is equal to 1.5 tons of dust per a day. It is here that the possibility of transporting pollutants over long distances is most often realized. Coarse dust discharged through the ventilation systems of mines is intensively deposited in the sanitary protection zones of mines. Fine dust is carried by the wind outside them, polluting the environment on the distance of up to 3500 m from the coal mine. Emissions of carbon dust into the atmosphere are almost always a major part of transboundary environmental pollution. Mine waste also poses an environmental threat. Technologies of reduction air pollution at the source of carbon-containing dust formation should be used in all new industries of economy. The results obtained reveal the mechanism of interaction of the sprayed liquid with coal dust and can be used in the development of new effective means of controlling the carbon-containing dust. The principles and practices of sustainable development, coupled with local research, will help to contain or eliminate health and environmental risks resulting from air pollution by carbon-containing dust.

Development of machine for collection of cement dust

One of the negative changes in the Earth’s ecosystem is air pollution from cement production waste. Cement industry enterprises annually emit more than 27 million tons of dust into the environment. They account for 2/3 of industrial emissions of solid substances and 44% of gaseous ones. The construction of various facilities is increasing every year. This leads to increased cement production and additional pollution. The most dangerous is fine dust (particle size less than 10 microns). It was found that a significant part of the fine dust is carried away by the exhaust gases even before entering the stage of dry cement formation. It is deposited in various production facilities. Further dust can enter the atmosphere from the workshops and cause pollution. Collecting it is a very complicated and expensive process. In the article, the design of a machine for collecting and unloading cement dust makes it possible to collect about 69% of all dust in the workshop and on the territory of the plant and load it into a special container. This significantly improves the ecological state of the air.

Mt. Wendelstein imaging of comet 41P/Tuttle-Giacobini-Kresak during the 2017 perihelion arc

Context.In April 2017 comet 41P/Tuttle-Giacobini-Kresak (41P) passed perihelion close to Earth.Aims.We present observations of the comet and aim to use these to characterize its dust environment in the coma and of physical properties of the nucleus.Methods.41P was imaged in the visible at the Mt. Wendelstein observatory over 45 nights between 2017 March 11 and 2017 July 17. Photometry of the coma provides information on the dust activity of the comet. Nucleus dimensions are determined by comparing radial profiles of observed images with those from models of the brightness distribution in the near-nucleus coma. Coma and tail structures in the images are enhanced using adaptive Laplace filtering and image normalization techniques. The geometry of the coma structures found are compared to results from dust models of the comet in order to obtain information on the nucleus rotation axis and the location of active regions on the nucleus.Results.Analyzing the evolution of the dust activity of the comet versus solar distance gives different results depending on the assumed phase angle corrections for the dust. Contamination from light emissions of the coma gas modified the colors in the coma and the slopes of the radial profiles. The light distribution in the very inner coma indicates some dust fragmentation close to the nucleus. The appearance of a prominent coma fan during the time period from March to May 2017 constrains the rotation axis of the nucleus (52 deg obliquity, 50 deg rotation angle of the perihelion meridian). This fan is produced by an extended region beyond about 50 deg latitude on the nucleus. Two narrow regions at low northern to equatorial latitudes were responsible for the time-variable occurrence of linear dust jets in the coma. An outburst of about 0.6 mag on 2017 May 11 generated various dust structures in the coma. The outburst originated from a region extending over a latitude range from +30 deg to −5 deg and released about 3000 tons of dust into the coma. The brightness of the nucleus indicates an equivalent radius of about 600 m and a minimum axis ratio larger than two.

Ecological functions of forest stands in urbanized environment of Moscow

In urban forests, stock production is not the main function of stands. Carbon sequestration, the release of oxygen and phytoncides, dust precipitation, and changing wind conditions et al. are the main environmental functions. Phyto-organic substances emitted by trees help to reduce the number of microorganisms in air make the air cleaner and fresher. The purpose of the study is to evaluate the ecological functions of forest stands based on long-term observations of the forest stands of the Forest Experimental District of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy. The study used data about 7 permanent trial plots in natural pine stands, 7 - in pine plantations (planting density - 32 000 trees per 1 ha), 13 - in larch plantations (planting density - 700-4000 trees per 1 ha), 8 - in oak stands (natural stands and plantations) and 9 - in birch stands (natural stands and plantations). For a year, 1 ha of forest covered area produces 10 tons of oxygen, and the entire territory of the Forest Experimental District produces about 2.5 thousand tons of oxygen. In the year, the stands of the Forest Experimental District absorb about 3 thousand tons of carbon dioxide. The forest stands of the Forest Experimental District are capable of precipitating 135 tons of dust and they emit about 130 tons of phytoncides into the air during the growing season. Under urban conditions, forest stands are subject to the influence of negative factors: emissions from industrial enterprises and transport, recreational loads, disruption of natural conditions, and many others. Negative factors lead to a decrease in the performance of ecological functions. Therefore, in urban forests it is necessary to carry out silvicultural measures to increase the sustainability and productivity of stands.

Missing Mass and Galactic Dust with a Size Greater than 200 Microns, Minimum Size of the Micrometric Dust around the Sun

The studies of the glaciologists show that, since 30,000 years, the Earth receives every year approximately 40,000 tons of dust, dust with an average size about 200 microns. By determining of which volume these 40,000 T come and by showing that the density of this volume is significant within the density of the milky way, I have tried to estimate the mass of dust contained in the Galaxy. To support that this density close to earth is representative, arguments are given: 1) the distribution of great dust is largely homogeneous in the galaxy (what does not exclude the existence of gas or dust clouds with different densities in the milky way); 2) there would be a minimum size that I have calculated for micrometeorites in the solar environment, and so there would be a lack of the micrometeorites with a size between 5 and 50 microns. So the density would not be greater in the solar system. Next, a very simple rough calculation (as the one made by the observatory of Paris in 1910) allows estimating this mass near 4 times that of the dark matter. So, the interstellar dust with a large size (>200 μ) could it be the missing mass? A verification method is proposed to confirm or refute this hypothesis.

The reduction of atmospheric emissions after the implementation of first Polish nuclear power plant

In this work the environmental benefits in the atmospheric emissions after the implementation of 3,000 MW nuclear power plants were assessed and presented. To determine the quantity of avoided emissions of CO2, NOx, SO2 and Hg compounds, harmonised stoichiometric combustion model dedicated to solid fuel fired power plant was created. To increase the credibility of the studies, future strict emission standards (Directive 2010/75/EU, BAT documents for LCP) were included as well. In conducted studies, representative samples of 3 different Polish solid fuels were examined (by comprehensive proximate and ultimate analysis) and used in assessment. It was proven that by the replacement of thermal solid fuel power plant by nuclear unit (with annual production rate of 22.4 TWh net) up to 16.4 million tonnes of lignite, 8.9 million tonnes of hard coal or 13.1 million tonnes of solid biomass can be saved. Further, for the case of lignite, the emission, at least, of 21.29 million tonnes of CO2 (6.9% of all Polish emission in 2015), 1,610 tonnes of dust (0.4%), 16,102 tonnes of NOx (2.2%), 16,102 tonnes of SO2 (2.0%) and 564 kg of mercury (5.9%) can be avoided. For selected hard coal, calculated emission savings were equal to 17.60 million tonnes of CO2 (5.7%), 1,357 tonnes of dust (0.4%), 13,566 tonnes of NOx (1.9%), 13,566 tonnes of SO2 (1.7%), 271 kg of mercury (2.9%), and for biomass - equal to 20.04 million tonnes of CO2 (6.5%), 1,471 tonnes of dust (0.4%), 14,712 tonnes of NOx (2.0%), 14,712 tonnes of SO2 (1.8%) and 294 kg of mercury (3.1%).

The use of expanded clay dust in paint manufacturing

Production increase of useful products is accompanied by the formation and the accumulation of the vast amounts of industrial wastes, the bulk of which is not involved in the recycling processes. An example of such wastes is dust bag filters of ceramsite production. At the large enterprises, the volume of its formation can reach 7-8 tons of dust per day, which is 10-15% of feedstock mass. The studies on the use of ceramsite production dust as filler pigment in the composition of organic mixed primer of red-brown color are carried out in this work. For comparison, red iron oxide pigment (Pg FGM) was used. The results showed that, primer with the use of expanded clay dust is characterized by the short drying time and meets all regulatory requirements.

Liquid lithium loop system to solve challenging technology issues for fusion power plant

Steady-state fusion power plant designs present major divertor technology challenges, including high divertor heat flux both in steady-state and during transients. In addition to these concerns, there are the unresolved technology issues of long term dust accumulation and associated tritium inventory and safety issues. It has been suggested that radiation-based liquid lithium (LL) divertor concepts with a modest lithium-loop could provide a possible solution for these outstanding fusion reactor technology issues, while potentially improving reactor plasma performance. The application of lithium (Li) in NSTX resulted in improved H-mode confinement, H-mode power threshold reduction, and reduction in the divertor peak heat flux while maintaining essentially Li-free core plasma operation even during H-modes. These promising results in NSTX and related modeling calculations motivated the radiative liquid lithium divertor concept and its variant, the active liquid lithium divertor concept, taking advantage of the enhanced or non-coronal Li radiation in relatively poorly confined divertor plasmas. To maintain the LL purity in a 1 GW-electric class fusion power plant, a closed LL loop system with a modest circulating capacity of ~1 l s−1 is envisioned. We examined two key technology issues: (1) dust or solid particle removal and (2) real time recovery of tritium from LL while keeping the tritium inventory level to an acceptable level. By running the LL-loop continuously, it can carry the dust particles and impurities generated in the vacuum vessel to the outside where the dust/impurities can be removed by relatively simple dust filter, cold trap and/or centrifugal separation systems. With ~1 l s−1 LL flow, even a small 0.1% dust content by weight (or 0.5 g s−1) suggests that the LL-loop could carry away nearly 16 tons of dust per year. In a 1 GW-electric (or ~3 GW fusion power) fusion power plant, about 0.5 g s−1 of tritium is needed to maintain the fusion fuel cycle assuming ~1% fusion burn efficiency. It appears feasible to recover tritium (T) in real time from LL while maintaining an acceptable T inventory level. Laboratory tests are being conducted to investigate T recovery feasibility with the surface cold trap concept.

Impacts of Stone Mining and Crushing on Stream Characters and Vegetation Health of Dwarka River Basin of Jharkhand and West Bengal, Eastern India

Abstract Dwarka River basin (3882.71 km2) of Eastern India in the Chotonagpur Plateau and Gangetic Plain is highly affected by stone mining and crushing generated dust. In the middle catchment of this basin, there are 239 stone mines and 982 stone crushing units. These produce approximately 258120 tons of dust every year and this dust enters into the river and coats the leaves of plants. On the one hand, this is aggrading in the stream bed, increasing sediment load, decreasing water quality, specifically increasing total dissolved solid, pH, water colour, and it also degrades the vegetation quality. Vegetation quality is also degraded as indicated by decreasing of NDVI values (maximum NDVI in 1990 was 0.70 and in 2016 it was 0.48). Considering all these issues, the present paper intends to identify dust vulnerable zones based on six major driving parameters and the impact of the dust on river morphology, water quality and vegetation quality in different vulnerable zones. Weighted linear combination method (in Arc Gis environment) is used for compositing the selected parameters and deriving vulnerable zones. Weight to the each parameter is assigned based on analytic hierarchy process, a semi quantitative method. According to the results, 579.64 km2 (14.93%) of the catchment area is very highly vulnerable: Here 581 rivers have a length of 713 km and these riversare prone to high dust deposition, increased sediment load and water quality deterioration.

Determination of Leaf Dust Accumulation on Certain Plant Species Grown Alongside National Highway- 22, India

Vehicular traffic is one of the major contributors to accumulate dust on plants grown alongside roads. Plants intercept tons of dust, absorb noise and serve as acoustic screens on busy highways. Vegetation contributes in reducing dust concentration in environment by acting as a sink for air pollutants. Taking this into account, the present study was conducted on National highway- 22 from Parwanoo to Solan, falling in Solan district of Himachal Pradesh, India. Specifically, four plant species namely Grewia optiva Drummond ex Burret, Toona ciliata M. Roem, Melia azedarach L. and Woodfordia floribunda (L.) Kurz of uniform size, age, spread and common in occurrence on both sides of the highway were selected for the study. Dust accumulation on leaves of selected plants was estimated during three main seasons (Rainy, Winter and Summer) of the year. Samples were collected from two horizontal distances (0-5 m and 5-10 m) from both sides of the road. Results showed that dust accumulation on the leaves ranged from 0.0083 g m-2 in T. ciliata to 0.0597 g m-2 in G. optiva and followed the descending order G. optiva > W. floribunda > M. azedarach > T. ciliata. Season wisethe examined plant species followed the descending order winter > summer > rainy season. Plants grown at a distance of 0-5 m accumulated higher dust on their leaves as compared to 5-10 m distance from the road. Due to surface characteristics of twigs, bark and foliage of the plants particulate matters are captured by them and remain there for extended time period. From the results of this study, it could be inferred that the air quality in urban/ arid areas can be improved by planting firstly the species G. optiva and W. floribunda along road sides of similar highways to national highway-22.

Hydrometallurgical Treatment of EAF Dust by Direct Sulphuric Acid Leaching at Atmospheric Pressure

The present paper presents a part of the research efforts of the laboratory of Metallurgy, National Technical University of Athens, Greece, aiming at developing a purely hydrometallurgical method, able to treat the zincferous dust, generated during the production of steel from scraps in Electric Arc Furnace (EAF), efficiently and economically and especially so for annual capacities lower than 50,000 tonnes of dust, for which the currently applied industrial methods are not economical. The proposed method is based on direct sulphuric acid leaching of the EAF dust and it succeeds to recover the valuable metals contained in it, such as zinc, lead and cadmium, converting the initially hazardous waste into a residue suitable to be fed to cement industry. The EAF dust sample, provided by a Greek steel plant, was initially leached with water, at certain conditions, to remove as much of the contained calcium as possible without co-dissolution of other metals. The washed dust was further subjected to three–stage leaching at atmospheric pressure, using sulphuric acid concentrations of 2N and 3N and temperatures 25 °C, at the first stage, and 95 °C, at the second and third stages. Total percent extraction values achieved were 97 % for zinc and 97 % for cadmium. Almost all lead, 99.7 %, remained undissolved as lead sulphate in the leach residues. It was shown experimentally that lead can be recovered as saleable lead sulphide while zinc can be recovered from the pregnant solution by solvent extraction with D2EHPA. Finally, based on the results, a conceptual flowsheet of the proposed integrated hydrometallurgical method for the treatment of EAF dust was established and is given.

Furnace dust utilisation using the pneumatic injection: a methodology

The issue of generating dust waste is present in steel and foundry plants around the world, as all melting furnaces generate tonnes of dust every year. This dust is obviously considered to be a waste material; however, the dust itself still contains certain chemical elements (mostly iron and zinc) which can be utilised by being returned to the furnace during the melting process. This means increasing their content in the liquid metal bath or in the dust that is finally sucked out from the furnace that can then be used as a raw material in the zinc metallurgy industry. There are several methods to achieve this, and one of them is pneumatic powder injection with the use of a pneumatic dust feeder and injection lance to introduce the dust directly under the surface of liquid metal. The paper presents both a theoretical approach as well as industrial applications as the result of the authors’ work in this field of the pneumatic conveying technique. Both the benefits and limitations of dust reuse are presented. The same method can be used to re-introduce cupola dust into the cupola and electric arc furnace together with some carburiser or ferroalloy additions. The results show the crucial influence of the process’s pneumatic and dimensional parameters that are needed to achieve proper jet penetration inside the liquid metal volume. The authors’ own theoretical formula for the so-called critical jet radius describing its potential to penetrate the liquid alloy is shown here, too. This complex approach has proven to be a huge potential of the pneumatic powder injection technique as a tool to utilise dust wastes in melting furnaces in steel and foundry plants.

The Siding Spring cometary encounter with Mars: A natural experiment for the Martian atmosphere?

AbstractOn 19 October 2014 comet C/2013 A1 will encounter Mars. The planet is anticipated to pass through the coma resulting in a greater than four order‐of‐magnitude increase in the accretion of dust with 430 tonnes of dust with diameters between 1 µm and 12.4 mm surviving atmospheric passage. At high altitude, the dust would impact temperature and may affect limb dust extinction and cloud formation. The UV photolysis of the organic carbon content of the dust, 1.9 to 4.6 tonnes, would have a negligible effect on atmospheric methane. Should C/2013 A1 brighten, increases in upper atmospheric accretion of coma particles will exceed the background dust and the population of small coma particles may be constrained from orbital measurements. For M1 < –1.3, methane produced might be measurable by the Sample Analysis at Mars Tunable Laser Spectrometer instrument onboard Curiosity.