Dust Particles Research Articles

Long-range transport of coarse mineral dust: an evaluation of the Met Office Unified Model against aircraft observations

Abstract. Coarse mineral dust particles have been observed much further from the Sahara than expected based on theory. They have impacts different to finer particles on Earth's radiative budget, as well as carbon and hydrological cycles, though they tend to be under-represented in climate models. We use measurements of the full dust size distribution from aircraft campaigns over the Sahara, Canaries, Cabo Verde and Caribbean. We assess the observed and modelled dust size distribution over long-range transport at high vertical resolution using the Met Office Unified Model, which represents dust up to 63.2 µm diameter, greater than most climate models. We show that the model generally replicates the vertical distribution of the total dust mass but transports larger dust particles too low in the atmosphere. Importantly, coarse particles in the model are deposited too quickly, resulting in an underestimation of dust mass that is exacerbated with westwards transport; the 20–63 µm dust mass contribution between 2 and 3.7 km altitude is underestimated by factors of up to 11 in the Sahara, 140 in the Canaries and 240 in Cabo Verde. In the Caribbean, there is negligible modelled contribution of d > 20 µm particles to total mass, compared to 10 % in the observations. This work adds to the growing body of research that demonstrates the need for a process-based evaluation of climate model dust simulations to identify where improvements could be implemented.

Observation of self-excited oscillations in DC glow discharge dusty plasma

We present a detailed experimental study of discharge current oscillations in a planar cathode plasma with poly dispersed alumina dust particles. Our experimental measurements suggest that surface density of dust particles play an important role together with cathode spots, in deciding self excited oscillating regime or stable dust cloud regime. Experiments conducted with dust particles density below the critical limit shows self excited oscillations. Operating above the critical limit, a dust cloud levitated in the sheath region was observed.

MANTA-Ray: Supercharging speeds for calculating the optical properties of fractal aggregates in the long-wavelength limit

Abstract Correctly modelling the absorptive properties of dust and haze particles is of great importance for determining the abundance of solid matter within protoplanetary disks and planetary atmospheres. Rigorous analyses such as the discrete dipole approximation (DDA) can be used to obtain accurate absorption cross-sections, but these require significant computing time and are often impractical to use in models. A simple analytical equation exists for spherical particles in the long-wavelength limit (where the wavelength is much larger than the size of the dust particle), but we demonstrate that this can significantly underestimate the absorption. This effect is found to depend strongly on refractive index, with values of m = 1 + 11i corresponding to an underestimate in absorption by a factor of 1,000. Here we present MANTA-Ray (Modified Absorption of Non-spherical Tiny Aggregates in the RAYleigh regime): a simple model that can calculate absorption efficiencies within 10-20% of the values predicted by DDA, but 1013 times faster. MANTA-Ray is very versatile and works for any wavelength and particle size in the long wavelength regime. It is also very flexible with regards to particle shape, and can correctly model structures ranging from long linear chains to tight compact clusters, composed of any material with refractive index 1+0.01i ≤m ≤ 11+11i. The packaged model is provided as publicly-available code for use by the astrophysical community.

Experimental investigation on the performance of a two-stage electrostatic precipitation at corona discharge

In this paper, our attention has been focused on the effect of the presence of dust particles on the characteristics of the corona discharge in an ESP electrostatic precipitator in wires to plate configuration. Different parameters are taken into account, in particular the influence of the polarity, of the source of continuous electric excitation, the number of active electrodes and the dimensions of the particles of the dust. The dust used is recovered in the chimney of a cement plant is sieved to have different particle sizes 80,250 and 500μm. Dust particles pass through the inter-electrode space. By corona effect, there will be an ionization of the gas around the wire, and creation of ions and electrons. The latter bombard the dust that is charged with electricity and are then attracted to the surface of the plates under the effect of the electric field. Dust is deposited on the plate electrodes. A model in the laboratory was used for the measurement of the discharge current and to plot the I-V characteristic as a function of the number of active electrodes in absence and in the presence of different dimensions of the particles of the dust particles.

Common Contaminants Of Blood Group Factors And Its Effect On Blood Groups In Blood Samples, Collected At Scene Of Crime

For detection of crime in Forensic medicine blood group studies& its application plays an important role. The study of blood grouping gives important information regarding identification and details of Crime Investigation. The most common trace evidence is blood which is obtained from the crime scene. Blood grouping & typing can point to a group of people that have the same blood type rather than pointing particular person. When blood is properly collected and preserved, blood as an evidence can establish a strong link between a criminal and the criminal act. We can trust the blood grouping of blood stains in detection of crime. Randomly A, B, AB, Rh positive blood samples were taken in duplicates and rusted pins, dust particles, detergent, staphylococci are added to it respectively. The common contaminants in blood stains are dust, rust, bacteria and detergent. So an effect of these on blood groups was studied in detail.

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.

Research on visual features and identification of coal and gangue in simulated underground mine environments

ABSTRACT In underground mine environments, factors such as low light intensity, diffusion of dust particles, and coal slurry coverage interfere with coal gangue identification. To further realize coal-gangue sorting underground, we analyzed the coal-gangue visual characteristics coupled with the above factors. The analysis reveals that both smoke environments and coal slurry coverage tend to make the coal-gangue visual features more consistent. There are still differences in coal-gangue visual features under smoke environments, while coal slurry coverage leads to gangue exhibiting coal-related feature information. To improve the detection capability of coal gangue in underground environments, this study adopts a coal gangue recognition method based on the DG module and YOLOX-PSB network: Utilize the DG module to achieve dehazing and then use the YOLOX-PSB model for object detection. The proposed method was validated through ablation experiments, and the results showed that the detection accuracy reached 99.6%, with an FPS of 98. The proposed method enables real-time detection and exhibits the best robustness in complex environments, realizing reliable and efficient performance.

Capture and tracing interstellar and interplanetary dust particles through the China Space Station

Capture and tracing interstellar and interplanetary dust particles through the China Space Station

Aluminum dust concentration detection based on LSTM-Kalman filter

Industrial dust emissions present serious hazards, including respiratory issues and explosion risks. Traditional dust concentration detection methods are often compromised by environmental factors. This study introduces a novel FFT-KF-LSTM-NET model to predict high-concentration aluminum powder levels, utilizing 128 sets of electrostatic induction measurement data. By applying the Fast Fourier Transform (FFT) to eliminate low-frequency interference, integrating Long Short-Term Memory (LSTM) networks for advanced time series analysis, and using the Kalman Filter (KF) for rapid model convergence, this approach significantly enhances prediction accuracy. The model achieves an 82% improvement in Mean Squared Error (MSE), reducing it to 0.1336, outperforming traditional methods. Furthermore, by modeling the voltage signal generated by charged dust particles in the electrostatic induction sensor's sensing area and using the first derivative of the voltage signal as a learning feature, the model's prediction speed is increased from 1.5 s-2 s–0.5 s, with improved anti-interference capabilities. These advancements position the FFT-KF-LSTM-NET model as a crucial tool for real-time, reliable dust concentration detection in industrial environments.

The process of superdeep penetration of high-speed metallic particles in solid body

An explanation of the effects arising at the collision of a stream of metal particles with a size of 10–100 microns, moving at a speed of 1–3 km/s, with a solid target is proposed. It is assumed that at the moment of impact on the target, the particle loses some electrons and for some time, due to the presence of an oxide shell, retains a positive charge. The flow of electrons passing through the target at the moment of impact generates an electromagnetic field pulse. A particle with a charge of about 10–9 C, having penetrated into a solid target, presses on the channel wall with a force of about 500 MPa and moves in it under the action of forces caused by the polarization of the target substance. The combination of high pressure and displacement leads to a significant reduction in the particle-wall friction force. The proposed hypothesis, if confirmed, can help find ways to protect electronic devices of spacecraft from impacts from streams of fast dust particles.

Saharan dust and respiratory health: Understanding the link between airborne particulate matter and chronic lung diseases (Review).

Saharan dust storms, which originate from the Sahara desert, have a significant impact on global health, especially on respiratory conditions of populations exposed to fine particulate matter that travels across continents. Dust events, characterized by the transport of mineral dust such as quartz and feldspar, lead to the suspension of particulate matter in the atmosphere, capable of traversing long distances and affecting air quality adversely. Emerging research links these dust episodes with increased incidence and exacerbation of lung diseases, including asthma and chronic obstructive pulmonary disease, especially during peak dust emission seasons from November to March. The present review aims to synthesize existing scientific evidence concerning the respiratory health impacts of Saharan dust, examining the environmental dynamics of dust transmission, the physical and chemical properties of dust particles, and their biological effects on human health. Further, it assesses epidemiological studies and discusses public health strategies for mitigating adverse health outcomes. Given the complexity of interactions between atmospheric dust particles and respiratory health, this review also highlights critical research gaps that need attention to better understand and manage the health risks associated with Saharan dust.

Modeling and Simulation of Sand Particle Trajectories and Erosion in a Transonic Fan Stage

Abstract In desert regions, the high concentrations of dust and sand particles carried by storms are sucked into aircraft engines, leading to severe erosion. This numerical study analyses the movement of sand particles and the erosion process in the front components of a high-bypass turbofan engine (HBTFE). The components include the Pitot intake, spinner, fan, core flow inlet guide vanes (IGVs), and secondary flow outlet guide vanes (OGVs). The study focuses on the engine operating conditions during takeoff from a Saharan airfield. The flow field data is obtained separately, and exported to an in-house particle tracking code based on the Lagrangian approach. The finite element method (FEM) is used to track the particles as they move through the mesh cells and determine the precise impacts and conditions to calculate the local erosion rates and material removal. Obtained results indicate large numbers of sand particles impacting the fan blade at high frequency from the hub up to approximately 80% of the span, due to their deflection by the Pitot intake lip and outer contour. The pressure side (PS) of the fan blade experiences extreme erosion rates, while the highest erosion rates occur at the leading edge (LE) and towards the trailing edge (TE). At the exit of the fan blade, a significant amount of particles pass through the OGVs and typically erode its PS, while fewer particles from the lower sections of the fan pass through the IGVs. These findings reveal the erosion-prone areas that need special coating protection.

Particle Size and Morphological Evaluation of Airborne Urban Dust Particles by Scanning Electron Microscopy and Bidimensional Empirical Mode Analysis

Airborne particles affect the health of the population. As particles decrease in size, they can penetrate deeper into the respiratory system, reaching the terminal bronchioles and alveoli. Particles as small as 0.1 µm in diameter may translocate into the bloodstream, potentially impacting various organs. Additionally, the smaller the particle size, the longer they remain suspended in the air, thereby increasing their deleterious damages. The aim of this work is to study the size distribution of airborne particles emitted from anthropogenic sources of air pollution, with a special emphasis on estimating the distribution of micro and nanoparticles considered the most harmful to health. The Bidimensional Empirical Mode Decomposition (BEMD) algorithm was used on micrographs of the particles obtained by Scanning Electron Microscopy (SEM). BEMD is a current empirical computational tool applied to image analysis that allows extracting non-linear heterogeneous oscillations of brightness. We studied ROFA (Residual Oil Fly Ash) from industrial sources and DEP (Diesel Exhaust Particles) from vehicular emissions as airborne particles. After collecting the particles on filters, micrographs were taken using SEM at different magnifications to which the BEMD algorithm was applied. Particle size and asymmetry distributions were obtained for each mode, allowing the identification of the most deleterious particles. The methodology employed herein is relatively simple and effective for inferring the impact of airborne particulate matter on health and the environment.

Research on a Photovoltaic Panel Dust Detection Algorithm Based on 3D Data Generation

With the rapid advancements in AI technology, UAV-based inspection has become a mainstream method for intelligent maintenance of PV power stations. To address limitations in accuracy and data acquisition, this paper presents a defect detection algorithm for PV panels based on an enhanced YOLOv8 model. The PV panel dust dataset is manually extended using 3D modeling technology, which significantly improves the model’s ability to generalize and detect fine dust particles in complex environments. SENetV2 is introduced to improve the model’s perception of dust features in cluttered backgrounds. AKConv replaces traditional convolution in the neck network, allowing for more flexible and accurate feature extraction through arbitrary kernel parameters and sampling shapes. Additionally, a DySample dynamic upsampler accelerates processing by 8.73%, improving the frame rate from 87.58 FPS to 95.23 FPS while maintaining efficiency. Experimental results show that the 3D image expansion method contributes to a 4.6% increase in detection accuracy, an 8.4% improvement in recall, a 5.7% increase in mAP@50, and a 15.1% improvement in mAP@50-95 compared to the original YOLOv8. The expanded dataset and enhanced model demonstrate the effectiveness and practicality of the proposed approach.

Эффект интенсивного окисления сероводорода дымовых газов содорегенерационного котла при производстве целлюлозы

Despite the transition to the Swedish technology for regenerating black liquor from pulp production plants, even in those regions of Russia where the standard daily average levels of hydrogen sulfide and methyl mercaptan in the air of populated areas have been achieved, a number of problems remain with emissions of reduced sulfur. In many cities, onetime concentrations of reduced sulfur, especially at night, may exceed the permissible ones. In addition to flue gas emissions from soda recovery boilers, there are other, less intensive sources of harmful emissions in the cooking, evaporation and wood-chemical workshops, in the causticization and lime regeneration workshops, there are emissions from unorganized sources and from the open surface of wastewater treatment facilities. The population living near such plants feels the unpleasant odor of methyl mercaptan. This study has aimed to develop a new technology for reducing gas emissions of reduced sulfur into the environment, applicaple for different sources. The results of testing an industrial installation for purification of gas emissions from a soda recovery boiler in a scrubber with nozzle irrigation have been presented. Based on the measurements of the technological parameters of the operation mode of the gas purification plant and the determination of the composition of the irrigation solution, the analysis of the results obtained has been performed. During the tests, a high degree of hydrogen sulfide capture at a low pH value has been achieved. It has been established that hydrogen sulfide has been captured as a result of its oxidation before entering the irrigation solution in fine droplets of condensate formed on micron-sized particles of sulfate and sodium carbonate. The results of this study have been compared with the results of the studies conducted by Stanford University and the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences. The possibility of hydrogen peroxide formation under our test conditions in the surface layer of fine droplets formed during the condensation of water vapour on dust particles has been analyzed. The suposed cause of the obtained effect has been determined to be the thermomechanical deformation of the surface layer of the droplets.

ЭМУЛЯЦИЯ ПОКАЗАНИЙ ДАТЧИКОВ КАЧЕСТВА ВОЗДУХА В ГОРОДСКОЙ СРЕДЕ УМНОГО ГОРОДА

Urban air pollution poses a serious threat to human health. To monitor it, both individual sensors and systems are used to assess the concentration of dust particles PM1, PM2.5, PM10 and organic compounds. However, the reliability of the sensor system cannot be 100 percent. From time to time, certain sensors in a distributed system fail. For this reason, it is very useful to emulate their readings based on the readings of the remaining sensors. The work describes a data set and proposes a machine learning model, which, based on the readings of functional sensors and weather conditions at the data collection sites, simulates the readings of a failed sensor. The accuracy of such emulation for certain types of pollution has been assessed (the coefficient of determination ranges from 0.43 to 0.61).

Tentative detection of cyclopropenylidene in comets

ABSTRACT We report the tentative detection of the ring molecule cyclopropenylidene (c-C$_3$H$_2$) in cometary comae. We observed three short-period comets: 73P/Schwassmann–Wachmann 3, 17P/Holmes, 103P Hartley 2, and two Oort Cloud comets: C/2007 N3 (Lulin) and C/2012 F6 (Lemmon) with the Arizona Radio Observatory Submillimeter Telescope (SMT) and the Atacama Large Millimeter/submillimeter Array (ALMA). We tentatively detected c-C$_3$H$_2$ in three of the comets, with molecule production rates in the range of $(0.2\!-\!3.8)\times 10^{25}$ molecules s$^{-1}$, and c-C$_3$H$_2$/H$_2$O mixing ratios of 0.01–0.19 per cent. Evidence from both the single-dish and interferometric data points to the presence of c-C$_3$H$_2$ being of a discrete transient nature and exhibiting an extended spatial distribution, indicating production from the decomposition of organic dust particles in the coma.

Performance of spherical and flat solar cells under different environmental conditions

This study investigates the performance degradation of spherical and flat solar modules due to dust accumulation. To isolate the effect of dust, both modules were subjected to identical environmental conditions, including irradiance, temperature, and humidity. The results reveal a significant reduction in power efficiency as dust density increases, with a nearly linear relationship observed. Spherical solar modules exhibited a minor decrease in efficiency (±3.64%) compared to flat solar modules (±5.46%) under increased dust density, consistent with prior research. Dust accumulation affects solar cells by causing dust deposition, light scattering, and temperature rise. Flat solar panels are more susceptible to dust accumulation due to their larger surface area, which attracts more dust particles. In contrast, spherical cells’ smaller surface area minimizes dust build-up, making them less prone to efficiency loss. The study also examined the impact of solar intensity and tilt angle on efficiency. Spherical cells demonstrated greater resilience in varying light conditions and tilt angles, maintaining efficiency across a wider range of scenarios than flat panels. These findings emphasize the importance of considering dust accumulation when designing and maintaining solar panels, with spherical modules offering advantages in dusty environments and under changing sunlight conditions.

Pemantauan Kualitas Udara Ambien pada Pekerjaan Preservasi Jalan

Heavy traffic, especially from large vehicles passing through the road, can potentially cause congestion and increase air pollution. Ambient air quality can significantly decrease due to vehicle emissions, impacting public health and environmental quality. This study focuses on monitoring ambient air quality during road preservation work conducted along the route of Jalan Bts. Prov. Sumsel – Tempino – Pal. Sepuluh – Lingkar Timur – Sp. Sijenjang – Pel. Talang Duku in Muaro Jambi Regency.objective of this research is to analyze the ambient air quality at th road preservation work sites. The research method applied is a survey method with the selection of three locations along the road segment: 1. AMP Tempino, located at coordinates LS 01°47’01.23’’ BT 103°28’27.56’’; 2. STA 11+050 located at coordinates LS 01°45’51’’ BT 103°33’23’’; and 3. Ruas Simpang Paal. X, located at coordinates LS 01°40’12’’ BT 103°36’1’’. This research is descriptive in nature, focusing on the observation and analysis of ambient air quality according to the SNI 7119-3:2017 standard for each test parameter. The results show that at the AMP Tempino site, Particulate dust is 46,50 µg/Nm³,Sulfur Dioxide is 99,88 µg/Nm³, and Carbon Monoxide is 6563,05 µg/Nm³. The highest Nitrgen Dioxide level of 47,88 µg/Nm³ was recorded at STA 11+050, and the highest level of Photochemical Oxidants as Ozone at 41,76 µg/Nm³ was found at Ruas Simpang Paal. X. All test parameters are below the standard quality limits. Overall, Carbon Monoxide has the highest concentration across all locations, while Nitrogen Dioxide often shows the lowest values

Contaminant dust effects on mist cooling in ribbed U-shaped channels of gas turbine blades

Mist cooling within turbine blades’ internal channels is a promising alternative to protect the blades from exceeding the temperature limit without additional coolant extraction. However, the presence of dust commonly encountered in harsh environments, such as deserts or sandstorms, can significantly affect cooling performance. This research employed numerical simulation methods and utilized the user defined function to direct the motion of mist/dust particles post-wall impact, to analyze the dust affected unsteady mist cooling effectiveness in a ribbed, U-shaped channel which is arranged within the blade to serve as a cooling passage. Additionally, this study examined the performance of mist cooling and heat transfer non-uniformity under various dust loading environments. The unsteady cooling mechanism of mist was discussed through the analysis of secondary flows induced by the inclined ribs and turning region. Enhanced cooling performance near the leading edge of the U-shaped channel was achieved by the coolant with mist under the action of a couple of vortices rotating in reverse. Moreover, this study revealed that dust particles exchanged heat with droplets and disrupted the flow fields, thereby altering the performance of mist cooling. These findings indicated that dust with smaller size, higher concentration, and greater specific heat significantly suppressed the mist cooling, but larger loading of dust led to an improvement in thermal uniformities within the channel.