Amount Of Dust Research Articles

Effects of meteorological factors on the retention of particulate matter in lawn grass blades

Plant leaves can reduce the concentration of atmospheric particulate matter (PM) by absorbing it in the air, and this mitigates the deleterious human health effects of PM. However, the ability of plant leaves to retain dust is limited and varies continually due to various meteorological factors such as rainfall, extreme wind speed, and PM10 concentrations. Here, we measured the ability of seven types of turfgrass with leaves similar in macromorphology but varying in micromorphology to retain dust particles of different sizes; we also analyzed the effects of various meteorological factors, such as rainfall, maximum wind speed, and PM10 concentration, on the ability of leaves to retain particles of different sizes. There were significant differences in the ability of the seven types of turfgrass to retain particles of different sizes; the dust retention capacity of Zoysia sinensis was the strongest(2.04 g·m-2), and that of Festuca elata was the weakest(1.39 g·m-2). The elution rates of PM>10 after rainfall of 3 mm and 4 mm were significantly higher than those of PM2.5-10 and PM2.5; the elution rates of PM>10, PM2.5-10, and PM2.5 increased as the amount of rainfall increased. When the amount of dust on leaves is low, wind promotes increases in leaf PM retention. When the blade retains a certain amount of dust, the maximum wind speed is greater than 9.1 m·s-1, which leads to a decrease in the dust retention of lawn grass blades. The concentrations of PM10 and PM2.5 were positively correlated with the retention of particles of different particle sizes. Therefore, evaluations of the dust retention ability of plant leaves require consideration of the effects of local rainfall, maximum wind speed, PM10 concentration, and other factors.

Planetary nebulae of the Large Magellanic Cloud II. The connection with the progenitors' properties

The study of planetary nebulae (PNe) offers the opportunity to evaluate the efficiency of the dust production mechanism during the very late asymptotic giant branch (AGB) phases, which allows us to assess the role played by AGB stars as dust manufacturers. We studied the relationship between the properties of PNe, particularly the gas and dust content, and the mass and metallicity of the progenitor stars to understand how dust production works in the late AGB phases and to shed new light on the physical processes the stars and the material in their surroundings are subject to in the period between the departure from the AGB and the start of the PN phase. We considered a sample of nine PNe in the Large Magellanic Cloud, seven of which are characterised by the presence of carbonaceous dust and the remaining two the presence of silicates. For these stars, we estimated the masses and the metallicity of their progenitor stars. We combined results from stellar evolution and dust formation modelling with results from analyses of the spectral energy distribution to determine the relation between the dust and gas mass of the PNe considered and the mass and metallicity of the progenitors. The physical properties of carbon-rich PNe are influenced by the mass of the progenitor star. Specifically, the dust-to-gas ratio in the nebula increases from $5 $ to $6 $ as the progenitor star's mass increases from approximately rm 0.9 M_ ⊙ to rm 2 M_ ⊙ . This change is partly influenced by the effective temperature of the PNe, and it occurs because higher-mass carbon stars are more efficient at producing dust. Consequently, as the progenitor's mass increases, the gas mass of the PN decreases since the larger amounts of dust lead to greater effects from radiation pressure, which pushes the gas outwards. No meaningful conclusions can be drawn from the study of the PNe with silicate-type dust, because the subsample comprises two PNe only, one of which is almost dust-free.

Tracing the Evolution of the Emission Properties of Carbon-Rich AGB, Post-AGB, and PN Sources

Understanding the transition from the Asymptotic Giant Branch (AGB) to the Planetary Nebula (PN) phase is crucial for advancing our knowledge of galaxy evolution and the chemical enrichment of the universe. In this manuscript, we analyze 137 carbon-rich, evolved low- and intermediate-mass stars (LIMSs) from both the Magellanic Clouds (MCs) and the Milky Way (MW). We focus on AGB, post-AGB, and PN sources, tracing the evolution of their emission through spectral energy distribution (SED) modeling. Consistent with previous studies, we observe that more evolved LIMSs exhibit cooler dust temperatures and lower optical depths. Amorphous carbon (amC) is the dominant dust species in all the evolutionary stages examined in this work, while silicon carbide (SiC) accounts for 5–30% of the total dust content. Additionally, we analyze color–color diagrams (CCDs) in the infrared using data from IRAC, WISE, and 2MASS, uncovering significant evolutionary trends in LIMS emission. AGB stars evolve from bluer to redder colors as they produce increasing amounts of dust. Post-AGB and PN sources are clearly differentiated from AGB stars, reflecting shifts in both effective stellar and dust temperatures as the stars transition through these evolutionary phases.

Evaluation of Compressive Strength of Concrete Using Stone Dust and Superplasticizer

Concrete, which is usually composed of cement, water, and fine and coarse aggregate, is the most dynamic building material for the construction of physical infrastructures because of its strength and durability, which solidifies over time in response to environmental changes. The size and shape of the aggregate have a significant impact on workability, strength, and durability of concrete since various particle sizes produce distinct reactions. To support the manufacturing of sustainable concrete, the research suggested substituting stone dust (SD) for sand. In contrast to the addition of stone dust, the application of superplasticizers improves the workability of concrete. The study aims to examine the compressive strength of M20-grade concrete that has superplasticizer added in addition to stone dust as fine aggregate replacement. The Maximum compressive strength of concrete has been achieved at 40% sand replacement. The findings revealed that the increase in stone dust content results in an increase in compressive strength of concrete using superplasticizer. The use of superplasticizer serves to increase the workability of the concrete and has no discernible effect on the compressive strength up to 50% sand replacement. The 28-days compressive strength achieved maximum value at 50% sand replacement with 2% superplasticizer. When stone dust and superplasticizer are added, the concrete becomes denser;conversely, when the amount of stone dust and superplasticizer is increased, the concrete becomes more slumped. For the construction of sustainable concrete, the SD can be used in place of fine aggregate in conjunction with superplasticizer.

Reduction of Iron Ore Pellets Containing Blast Furnace Dust

In the process of iron production in a blast furnace, a large amount of dust is generated as a by-product. The main components of this dust include iron and carbon, so a circular process should be implemented to protect the environment and reduce production costs. In this investigation, blast furnace dust (BFD) was used to produce pellets with iron ore as raw charging materials into the blast furnace. The mixture consists of BFD, iron ore, and 2 % in mass of bentonite as a binder in the pelletization process, with the ratio of BFD in the mixtures with fine iron ore being 0:100, 10:90, 20:80, and 30;70, respectively. Green pellets were dried at 105 °C for 24 hours obtaining dried pellets. Dried pellets are fired at 1200 °C in the atmosphere for 60 minutes to achieve the required mechanical properties obtaining fired pellets. The fired pellets were reduced at 1000 °C and 1100 °C for 45 minutes by coke breeze. XRD and SEM were then used to analyze the properties of the pellets. The results showed that the pellets exhibited improved metallurgical properties, making them suitable for charging material into the blast furnace.

Not just PAH_3.3: Why galaxies turn red in the near-infrared

We measured the spectral properties of a sample of 20 galaxies at $z 0.35$ selected for having surprisingly red JWST/NIRCAM F200W-F444W colors. Of these, 19 galaxies were observed with JWST/NIRSpec in the PRISM configuration, while the remaining galaxy was observed with the high-resolution gratings. Of the 20 galaxies in our sample, 17 exhibit strong 3.3 $ m$ polycyclic aromatic hydrocarbon (PAH) emission (equivalent width (EW) ( m$). In these galaxies, the strength of the color excess does not depend on environment and correlates with EW( Nonetheless, the presence of the alone cannot fully explain the color excess, as an EW of sim m$ is able to increase the color of galaxies by only 0.13 mag. A contribution from a hot dust component is required to explain the excess. Both the EW and flux correlate with the Halpha EW and flux, suggesting that they are produced by the same mechanism. Five of the galaxies of our sample showing would be classified as passive based on broadband rest frame colors ((B-V) and/or UVJ diagrams) and are hence ``faux passive". Of these, three galaxies have a significantly lower EW( given their color and also have low EW(Halpha ), and we tentatively conclude that this behavior is due to the presence of an active galactic nucleus. The three galaxies with no in emission have passive spectra, as do the eight galaxies in our sample with normal F200W-F444W colors. We therefore conclude that the feature is linked to dust-enshrouded star formation. The dust-corrected star formation rate (SFR) from is a factor of 3.5 higher than the SFR obtained from suggesting that these galaxies are characterized by significant amounts of dust.

Analysis of cytogenetic disorders in residents of an industrial region in connection with work at coal-fired thermal power plants

BACKGROUND: In the air of an industrial environment associated with the processing and combustion of coal contains a huge amount of coal dust, heavy metals, polycyclic aromatic hydrocarbons, which have a negative impact on genetic stability. In this regard, the purpose of the study is to study the genotoxic effects in workers of coal thermal power plants. MATERIALS AND METHODS: The paper presents a cytogenetic analysis of genomic damage in 455 coal-fired thermal power plant workers compared with 533 control donors from Kemerovo using a micronucleus test. The formation of genomic abnormalities in coal-fired thermal power plant workers was assessed in relation to sex, age, smoking status, presence of chronic diseases, length of service, and working shops. RESULTS: A significant increase in the frequency of occurrence of lymphocytes with micronuclei, nucleoplasmic bridges, nuclear buds, as well as cells at the stage of apoptosis in workers of coal-fired thermal power plants compared to the control group was established. An increase in the frequency of occurrence of cells with cytogenetic disorders was revealed in women working in coal production and workers over 51 years of age. Work experience and professional specialization had a significant impact on the formation of genomic disorders. CONCLUSIONS: The obtained results indicate a significant contribution of environmental factors to the development of geno- and cytotoxic effects in workers of coal-fired thermal power plants.

Granite Dust and Silica Fume as a Combined Filler of Reactive Powder Concrete.

By volume, cement concrete is one of the most widely used construction materials in the world. This requires a significant amount of Portland cement, and the cement industry, in turn, causes a significant amount of CO2 emissions. Therefore, the development of concrete with a reduced cement content is becoming an urgent problem for countries with a significant level of production and consumption of concrete. Therefore, the purpose of this article is to critically investigate the possibility of using inert granite dust in combination with highly active silica fume in reactive powder concrete. The main physical and mechanical properties, such as the compressive strength at different curing ages and the water absorption, were studied using mathematical planning of experiments. The consistency and microstructure of the reactive powder concrete modified with granite dust in combination with silica fume were also analyzed. Mathematical models of the main properties of this concrete are presented and analyzed, and the graphical dependencies of the influence of composition factors are constructed. A more significant factor that affects the compressive strength at all curing ages is the silica fume content, increases in which to 50 kg/m3 lead to a 25-40% increase in strength at 1 day of age, depending on the granite dust content. In turn, an increase in the amount of granite dust from 0 kg/m3 to 100 kg/m3 in the absence of silica is followed by an increase in strength of 8-10%. After 3 days of curing, the effect of granite dust becomes more significant. Increases in the 28-day strength of 25%, 46% and 56% were obtained at a content of 50 kg/m3 of silica fume and 0 kg/m3, 100 kg/m3 and 200 kg/m3 of granite dust in concrete, respectively. It is shown that the effect of inert granite dust is more significant in combination with silica fume at its maximum content in the range of variation. The pozzolanic reaction between highly active silica and Ca(OH)2 stimulates the formation of hydrate phases in the space between the grains and causes the microstructure of the cement matrix to compact. In this case, the granite dust particles act as crystallization centers.

Combining modeling and isotopic signatures to track Aeolian dust from source to sink in the Wasatch Front, Utah, USA

Dust events are tracked from source to sink using geochemical/isotopic tracers, dust emission and transport modeling, or remote sensing, but these tools are rarely used together. To test the utility of combining multiple dust tracking methods, we used three Wasatch Front (Utah) dust events from August 2009, May 2020, and September 2020 to compare source apportionment estimated by the Community Multiscale Air Quality (CMAQ) model and strontium isotope (87Sr/86Sr) ratios. The Wasatch Front is impacted by atmospheric particulate matter (PM) from local urban sources and regional playas including Sevier Dry Lake, Great Salt Lake (GSL), and the GSL Desert. CMAQ modeling of the August 2009 event showed dust emission and transport from multiple playa sources to the Salt Lake City measurement site as wind patterns changed during the storm. The predicted mix of sources was consistent with the measured87Sr/86Sr ratio of 0.71217 on the PM10filter collected during the event. Modeling of the May 2020 period showed a consistent meteorological pattern that carried dust from the Sevier Dry Lake area toward the Provo measurement site, consistent with the measured87Sr/86Sr ratio of 0.71015. Modeling of the September 2020 period indicated a major dust event with complex wind patterns that changed during the event, resulting in relatively small amounts of dust from GSL Desert being transported to the Provo site. No emissions from Sevier Dry Lake were predicted to reach the site during the September event, suggesting GSL Desert contributions were mixed with local dust with a lower 87Sr/86Sr ratio to produce the measured value of 0.71097. Results from the three dust events demonstrate the benefits of combining CMAQ emission and transport modeling with isotopic data from PM10filters to better characterize dust source-to-sink behavior in Utah, and illustrate the potential for application in other arid regions.

Assessment of Mechanical Behavior and Microstructure of Unsaturated Polyester Resin Composites Reinforced with Recycled Marble Waste

The quarrying and utilization of natural stones such as marble and granite are growing rapidly in developing countries. However, the processing, cutting, sizing, and shaping of these stones to render them functional generates huge quantities of waste and dust. These materials are often disposed of openly in the environment, and their potentially hazardous nature has negative repercussions on both the environment and human health. In this study, marble waste (MW) was used as a filler in the unsaturated polyester resin (UPR) matrix to enhance performance and characteristics while adding value to the waste and minimizing manufacturing costs. For this purpose, samples of UPR/MW composites were produced with 0, 5, 10, 15, and 20 wt.% of MW incorporated into the UPR. A full characterization that focused on the microstructure, thermal stability, and physical and mechanical properties was carried out. The results revealed that the use of 10 to 15% of MW improves mechanical performance, with increases from 17 to 26 kJ/m2, 14 to 17 MPa, and 794 to 1522 GPa in impact strength, tensile strength, and elastic modulus, respectively. By introducing a 20% MW filler, the composite loses its performance, particularly Shore D hardness, and becomes very brittle. Thermogravimetric analysis (TGA) indicated significant thermal stabilization, with a delay in the start decomposition temperature of 28 °C for 20 UPR/MW compared to 0 UPR/MW. Additionally, morphological and microstructural tests, namely, FT-IR, XRD, and SEM analysis, show a microstructural change, including the formation of crystalline phases, enhancing matrix-filler interactions due to the creation of Mg-O and Ca-O chemical bonds and the forming of filler agglomeration at high introduction rates that lead to defects in the microstructure. These results confirmed the mechanical results of the UPR/MW composites.

Insight on AGB Mass-Loss and Dust Production from PNe

The asymptotic giant branch (AGB) phase, experienced by low- and intermediate-mass stars (LIMSs), plays a crucial role in galaxies due to its significant dust production. Planetary nebulae (PNe) offer a novel perspective, providing valuable insights into the dust production mechanisms and the evolutionary history of LIMSs. We selected a sample of nine PNe from the Large Magellanic Cloud (LMC), likely originating from single stars. By modeling their spectral energy distributions (SEDs) with photoionization techniques, we successfully reproduced the observed photometric data, spectra, and chemical abundances. This approach enabled us to constrain key characteristics of the central stars (CSs), dust, and gaseous nebulae, which were then compared with predictions from stellar evolution models. By integrating observational data across ultraviolet (UV) to infrared (IR) wavelengths, we achieved a comprehensive understanding of the structure of the PNe in our sample. The results of the SED analysis are consistent with evolutionary models and previous studies that focus on individual components of the PN, such as dust or the gaseous nebula. Our analysis enabled us to determine the metallicity, the progenitor mass of the CSs, and the amount of dust and gas surrounding the CSs, linking these properties to the previous AGB phase. The PN phase provides critical insights into the physical processes active during earlier evolutionary stages. Additionally, we found that higher progenitor masses are associated with greater amounts of dust in the surrounding nebulae but lower amounts of gaseous material compared to sources with lower progenitor masses.

Environmentally Friendly Technologies Of Integrated Open Pit-Underground Mining

Abstract Kryvyi Rih iron ore basin is one of Ukraine’s oldest. Over 150 years of open pit mining has resulted in significant areas of arable land disturbed by open pits, dumps and tailings facilities. In Kryvyi Rih region, operation of open pits, dumps and tailings facilities results in worsened environmental conditions. Deep open pits and high dumps change the topography of the region. Open pits, dumps and tailings facilities not covered with vegetation contribute to bad air pollution by emitting large amounts of dust. To settle the environmental issues and preserve the nature in the basin, gradual transition from the technology of open-pit mining to integrated open pit-underground and subsequent underground mining is developed and proposed. In addition, the present paper addresses one of the main problems of geomechanical stabilization of the rock massif when constructing underground mines in areas of possible influence of open pit fields, and studies issues of controlling the stress-strain state of the rock massif during transition from the open-pit to integrated technology of deposit mining. The research conducted enables substantiation of technologies involving formation of internal waste rock dumps during integrated open pit-underground mining. The paper presents the results of the research on the stress-strain state of the massif during transition from the open-pit to integrated mining technology and proposes environmentally friendly technologies of integrated open pit-underground mining of deposits with waste disposal in the worked out space of underground mines and open pits. The Results Obtained Are Highly Relevant And Very Important In Both Scientific And Practical Fields.

Effect of the Type and Amount of Sedimented Sand and Clay Dust on the Energy of the Solar Panel

Background: The application of solar energy utilization in the world to generate electricity is established. The use of solar panels to generate electricity has witnessed steady scientific progress and plays a significant role in confronting environmental pollution. For solar panels, the efficiency depends to a large extent on the relationship between the solar radiation reaching the Earth’s surface and the dust layer covering the panels.In the case of a solar panel collecting a large amount of dust in its working place, the solar radiation is first diluted through the dust layer before it reaches the panel. This is the main reason for the decrease in the panel’s efficiency. Objectives: It is of utmost importance to study the effects of dust on the design of photovoltaic devices. The potential power reduction of panels due to dust is a pressing issue, with immediate consequences for the operation and number of panels in large solar power plants. This work aims to urgently study the effect of dust accumulation on the front surface of solar panels. Methods: The experiment is being conducted on two different solar panels: the first is monocrystalline with a power of 200 watts, and the second is polycrystalline with a power of 280 watts. Two types of dust – sand and clay – are being used in quantities ranging from 5 g to 25 g. Results: The introduction of sand dust led to a substantial decrease in the energy output of the monocrystalline solar panel, ranging from 3.3% to 7.5 %. Similarly, the use of clay dust resulted in a significant energy drop of 4% to 8%.While the energy of the polycrystalline plate decreased between 2.5% to 6.7% when using sand dust and between 3% to 7.1% when using clay dust. Conclusion: Our research uncovers the negative impact of dust on the efficiency of solar panels, particularly in the case of monocrystalline panels and those exposed to clay dust. This opens up avenues for further research and exploration in the field of solar technology.

Investigation of the Minimum Ignition Energy Required for Combustion of Coal Dust Blended with Fugitive Methane

Ventilation Air Methane (VAM) significantly contributes to global warming. Capturing and mitigating these emissions can help combat climate change. One effective method is the thermal decomposition of methane, but it requires careful control to prevent explosions from the high temperatures involved. This research investigates the influence of methane concentration and coal dust particle properties on the minimum ignition energy (MIE) required for fugitive methane thermal decomposition and flame propagation properties. This knowledge is crucial for the mining industry to effectively prevent and mitigate accidental fires and explosions in VAM abatement plants. Coal dust samples from three different sources were selected for this study. Experiments were conducted using a modified Hartmann glass tube and a Thermal Gravimetric Analyser (TGA). The chemical properties of coal dust were determined through ultimate and proximate analysis. The particle size distribution was determined using a Mastersizer 3000 apparatus (manufactured by Malvern Panalytical, Malvern, UK). The results showed that the MIE is significantly affected by coal dust particle size, with smaller particles (<74 µm) requiring less energy to ignite compared to coarser particles. Additionally, blending methane with coal dust further reduces the MIE. Introducing methane concentrations of 1% and 2.5% into the combustion space reduced the MIE by 25% and 74%, respectively, for the <74 µm coal dust size fraction. It was observed that coal dust concentration can either raise or lower the MIE. Larger coal dust concentrations, acting as a heat sink, reduce the likelihood of ignition and increase the MIE. This effect was noted at a methane concentration of 2.5% and coal dust levels above 3000 g/m3. In contrast, small amounts of coal dust had little impact on MIE variation. Moreover, the presence of methane during combustion increased the upward flame travel distance and propagation velocity. The flame’s vertical travel distance increased from 124 mm to 300 mm for a coal dust concentration of 300 g·m−3 blended with 1% and 2.5% methane, respectively.

An Optimized Stationary Wavelet Fusion Technique for Image de-hazing

Nowadays, the amount of smoke and dust in the air is increasing significantly due to industrialization. The smoke and dust particles accumulate in the relatively dry air and cause haze in the surrounding area, impairs visibility. This haze also affects photography, which reduces the images' quality and looks unnatural. The hazy atmosphere affects even pictures taken with a cell phone in everyday life. There are many methods to remove this haze content from the image, but they have not yielded great results. The long-time and short-time shots constantly differed while attempting to eliminate atmospheric haze from the images. To solve this problem, a fusion rule was proposed to fuse the luminance and dark channel prior (DCP) methods. The transmission estimated with the DCP method contributes mainly to the foreground regions, while the luminance model deals with the celestial regions. The fusion technique is a pixel-level fusion approach in the transform domain. The proposed approach combines the transmittance values obtained from the dark channel in front of the foreground region (background) and the luminance model for the sky region in the transform domain using the Stationary Wavelet Transform (SWT) with the optimized level of decomposition. The proposed algorithm was subjected to quantitative analysis of some statistical measures. The result shows that the proposed method successfully maintains the maximum visual truth content by effectively removing atmospheric haze from the images.

Assessment of the possibility of using waste aggregate dust for the production of vibro-pressed concrete paving blocks

Significant amounts of rock dust with a grain size similar to cement are generated during aggregate dedusting in the production of mineral-asphalt masses. These wastes are collected in tanks or silos and must be managed in such a way as not to generate costs related to disposal. On the other hand, the use of natural resources must be reduced in the production of cement composites. The objective of this research is to investigate the possibility of utilising aggregate dedusting waste (ADW) in vibro-pressed concrete paving blocks (VPCPB). Stage one of this research includes testing the compressive strength of concrete samples where cement was partially replaced by ADW or/and fly ash (FA). Stage two discusses the effect of cement replacement by ADW or FA on the splitting tensile strength of VPCPB. Using ADW in VPCPB is a promising option. Splitting tensile strength increased after both 7 and 28 days when ADW was used.

An X-Ray Significantly Variable, Luminous, Type 2 Quasar at z = 2.99 with a Massive Host Galaxy

We present a comprehensive X-ray analysis and spectral energy distribution (SED) fitting of WISEA J171419.96+602724.6, an extremely luminous type 2 quasar at z = 2.99. The source was suggested as a candidate Compton-thick (column density N H > 1.5×1024 cm−2) quasar by a short XMM-Newton observation in 2011. We recently observed the source with deep NuSTAR and XMM-Newton exposures in 2021 and found that the source has a lower obscuration of N H ∼ 5×1022 cm−2 with an about four times lower flux. The two epochs of observations suggested that the source was significantly variable in X-ray obscuration, flux, and intrinsic luminosity at 2σ–3σ in less than 2.5 yr (in the source rest frame). We performed SED fitting of this source using Code Investigating GALaxy Emission thanks to its great availability of multiwavelength data (from hard X-rays to radio). The source is very luminous, with a bolometric luminosity of L BOL ∼ 2.5 × 1047 erg s−1. Its host galaxy has a huge star formation rate (SFR) of ∼1280 M ☉ yr−1 and a huge stellar mass of ∼1.1 × 1012 M ☉. The correlation between the SFR and stellar mass of this source is consistent with what was measured in the high-z quasars. It is also consistent with what was measured in the main-sequence star-forming galaxies, suggesting that the presence of the active nucleus in our target does not enhance or suppress the SFR of its host galaxy. The source is an infrared hyperluminous, obscured galaxy with a significant amount of hot dust in its torus and shares many similar properties with hot, dust-obscured galaxies.

Experimental investigation of OH* emission spectrum characteristics and transient ignition dynamics in methane and coal dust mixtures explosions

Combustible gases, dusts and their mixtures are widely present in human production and life，and the fire and explosion disasters caused by them pose a serious threat to the field of energy security applications. Studying the ignition process of mixtures is essential for disaster risk assessment and safety protection. In this work, the explosion characteristics and OH* emission spectra of the mixtures were experimentally tested by varying the fuel equivalence ratio ( ER ≈ 0.79 ∼ 1.71), and the evolution of the transient flow field structure during the ignition process was quantitatively analyzed using the schlieren image velocimetry method. The results indicate that the emission spectrum of OH* is closely correlated with the maximum explosion pressure, and the spectral intensity of OH* at 306.4 nm is consistent with the maximum rate of explosion pressure rise. The flow field during the ignition process of the mixtures shows that a small amount of coal dust (concentration≤30 g/m3) can significantly promote flame acceleration and instability as the methane concentration is in lean combustion or stoichiometric ratio. However, when the concentration of coal dust increases (concentration≥40 g/m3), coal dust will suppress flame acceleration and instability. For methane concentration in fuel-rich combustion state, coal dust always suppresses flame acceleration and instability. The experimental results contribute to a further understanding of gas and coal dust mixed explosions and provide a verification database for the construction of chemical kinetic mechanisms.

Power attenuation of Martian rovers and landers solar panels due to dust deposition

Because of the high amount of dust in the Martian atmosphere, solar panels of landers and rovers on Mars get covered by dust in the course of their mission. This accumulation significantly decreases the available power over sols. During some missions, winds were able to blow the dust away. These ”dust cleaning events”, as they are called, were followed by an increase of the electrical current produced by the solar arrays. However, the Insight Lander solar panels were never cleaned and the mission died of dust accumulation. In order to better predict the evolution of available power produced by solar panels in the Martian conditions, this paper proposes a model of dust accumulation in which the solar flux under the accumulated dust layer is computed taking into account a full radiative transfer in the atmosphere and in the dust layer accumulated on the panel. This work uses several missions observation data to validate this model.

Advanced Study: Improving the Quality of Cooling Water Towers’ Conductivity Using a Fuzzy PID Control Model

Cooling water towers are commonly used in industrial and commercial applications. Industrial sites frequently have harsh environments, with certain characteristics such as poor air quality, close proximity to the ocean, large quantities of dust, or water supplies with a high mineral content. In such environments, the quality of electrical conductivity in the cooling water towers can be significantly negatively affected. Once minerals (e.g., calcium and magnesium) form in the water, conductivity becomes too high, and cooling water towers can become easily clogged in a short time; this leads to a situation in which the cooling water host cannot be cooled, causing it to crash. This is a serious situation because manufacturing processes are then completely shut down, and production yield is thus severely reduced. To solve these problems, in this study, we develop a practical designation for a photovoltaic industry company called Company-L. Three control methods are proposed: the motor control method, the PID control method, and the fuzzy PID control method. These approaches are proposed as solutions for successfully controlling the forced replenishment and drainage of cooling water towers and controlling the opening of proportional control valves for water release; this will further dilute the electrical conductivity and control it, bringing it to 300 µS/cm. In the experimental processes, we first used practical data from Company-L for our case study. Second, from the experimental results of the proposed model for the motor control method, we can see that if electrical conductivity is out of control and the conductivity value exceeds 1000 µS/cm, the communication software LINE v8.5.0 (accessible via smartphone) displays a notification that the water quality of the cooling water towers requires attention. Third, although the PID control method is shown to have errors within an acceptable range, the proportional (P) controller must be precisely controlled; this control method has not yet reached this precise control in the present study. Finally, the fuzzy PID control method was found to have the greatest effect, with the lowest level of errors and the most accurate control. In conclusion, the present study proposes solutions to reduce the risk of ice-water host machines crashing; the solutions use fuzzy logic and can be used to ensure the smooth operation of manufacturing processes in industries. Practically, this study contributes an applicable technical innovation: the use of the fuzzy PID control model to control cooling water towers in industrial applications. Concurrently, we present a three-tier monitoring checkpoint that contributes to the PID control method.