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Particles of fine dust are pollutants that adversely affect indoor air quality and exacerbate human respiratory diseases. The aging of the building was pointed out as a source of fine dust indoors. The aging of buildings has various causes of deterioration. During various deterioration, friction adversely affects the building floor finish. In this study, an accelerated friction deterioration device was used to confirm the generation of fine dust particles through the frictional deterioration of floor finishes in buildings. The study found that the concentration of fine dust particles attributed to deteriorating flooring was 327 mg/m3 in PM2.5 and 4828 mg/m3 in PM10 and confirmed that particle distribution differs depending on the surface of the flooring. Particles of 10 µm or less were observed through particle analysis. The study confirmed that fine dust particles did not diffuse in a specific direction and that the detected fine dust particles could be attributed to deterioration. Further research is needed on the detection of fine dust in degraded building finishing materials.

Exposure to dust particles containing toxic compounds is linked to serious health outcomes, including cancer. The purpose of this study was to determine if indoor dust from houses and cars contained harmful levels of brominated flame retardants (polybrominated diphenyl ethers, PBDEs) and polycyclic aromatic hydrocarbons (PAHs), and to assess their potential toxicity to adults and children. In Kuwait, the median concentration of total PBDEs (Ʃ14- PBDEs) was 408.55 μg PBDEs/kg dust in houses and twice as high in cars (838.52 μg PBDEs/kg dust), while total PAHs (Ʃ16-PAHs) were similar in houses (992.81 μg PAHs/kg) and cars (900.42 μg PAHs/kg). The PBDEs and PAHs concentrations in indoor dust were related to house age and square footage, car model year, and natural ventilation. Furthermore, a higher PBDEs concentration was associated with electronic devices that operate continuously, furniture containing foam treated with PBDEs, and cars that are parked outdoors, since PBDEs tend to be volatilized under these conditions. The PAHs concentration in indoor dust increased with smoking and proximity to major roads and industrial facilities, which are major PAHs sources. The hazard quotient and total cancer risk for PBDEs in indoor dust were within safe limits, but indoor dust with higher PAHs concentrations had hazard quotients from 5.51 to 11.23 and total cancer risk of 10−3 for adults and children. We conclude that exposure to PAHs-contaminated indoor dust from houses and cars where smoking occurs can increase the cancer risk of adults and children.

Indigo-dyed cotton weavers are exposed to various dust particles that may contain chemical contaminants from indigo fermentation process and can be related to respiratory symptoms. This cross-sectional study thus investigates the prevalence of respiratory symptoms and their association with respiratory dust (RD) exposure among workers in northeastern Thailand. It recruited 146 indigo-dyed cotton weavers. The prevalence of respiratory symptoms was collected by a self-report questionnaire included cough, phlegm, chest tightness, wheezing, and dyspnea. The average RD was 47.9 ± 28.3 μg/m3. Logistic regression models revealed a strong association between RD exposure and respiratory symptoms after adjustment. An exposure to RD ≥50 µg/m3 was associated with 5.05-, 3.58-, 2.88-, and 3.30-fold increased odds ratio of cough, phlegm, chest tightness, and dyspnea, respectively. The study results reveal that RD exposure may contribute to respiratory symptoms among indigo-dyed cotton weavers.

For fundamentally characterizing the effect of hierarchical structure in granular matter, a set of compression-relaxation tests for dust particles and glass beads confined in a cylindrical cell was performed. Typical diameter of both grains is approximately 1~mm. However, dust particles are produced by binding tiny ($\sim 5$~{\textmu}m) glass beads. The granular columns were compressed with a piston until reaching a maximum load force of 20~N with a constant compression rate $v$ ($0.17 \leq v \leq 2000$~{\textmu}m~s$^{-1}$). After that, the piston was stopped and the relaxation process was quantified. From the experimental results, we found that the compression force $F$ nonlinearly increases with the increase of compression stroke $z$ depending on particles. Besides, periodic undulation and sudden force drops were observed on $F(z)$ in dust particles and glass beads, respectively. The relaxation process was characterized by an exponential decay of stress followed by a logarithmic dependence one in both kinds of particles. These experimental findings are the main point in this study. To understand the underlying physics governing the compression mechanics, we assumed empirical forms of $F(z)$; $F\propto z^{\alpha}$ for dust particles and $F \propto \exp(z/z_G)$ for glass beads ($\alpha=2.4$ and $z_G=70$~{\textmu}m). Then, we found that the growing manners of periodic undulation and force drops were identical to those of mean compression forces, i.e., power law in dust particles and exponential in glass beads. In addition, the undulation amplitude and wavelength decreased as $v$ increased in dust-particles compression. On the basis of experimental results and the difference between dust particles and glass beads, we also discuss the origin of undulation and the physical meaning of granular-compression models used in engineering fields., Comment: 15 pages, 13 figures

The service life of machine component working under severe environment is a major issue in the industries. Machine component material continually gets degraded due to friction in mating parts, impingement of sand or dust particles on the surface. Higher temperatures in thermal power plants further escalate the degradation and affect the service life of the critical boiler parts/components, which causes the untimed shutdown. In this paper, some technological aspects are studied, which can be protective measures for degradation. The previous researches reveal that the use of protective coatings, hardfacing, friction stir processing etc. onto the surface of the machine component, improves the resistance to degradation. Improvements in microstructural and mechanical properties are significant factors that affect the life of the working component.

The spatiotemporal evolution and trends in aerosol optical depth (AOD) over environmentally distinct regions in Pakistan are investigated for the period 1980–2018. The AOD data for this period was obtained from the Modern-era retrospective analysis for research and applications, version 2 (MERRA-2) reanalysis atmospheric products, together with the Moderate-resolution imaging spectroradiometer (MODIS) retrievals. The climatology of AODMERRA-2 is analyzed in three different contexts: the entire study domain (Pakistan), six regions within the domain, and 12 cities chosen from the entire study domain. The time-series analysis of the MODIS and MERRA-2 AOD data shows similar patterns in individual cities. The AOD and its seasonality vary strongly across Pakistan, with the lowest (0.05 ± 0.04) and highest (0.40 ± 0.06) in the autumn and summer seasons over the desert and the coastal regions, respectively. During the study period, the annual AOD trend increased between 0.002 and 0.012 year-1. The increase of AOD is attributed to an increase in population and emissions from natural and/or anthropogenic sources. A general increase in the annual AOD over the central to lower Indus Basin is ascribed to the large contribution of dust particles from the desert. During winter and spring, a significant decrease in the AOD was observed in the northern regions of Pakistan. The MERRA-2 and MODIS trends (2002–2018) were compared, and the results show visible differences between the AOD datasets due to theuseof different versions and collection methods. Overall, the present study provides insight into the regional differences of AOD and its trends with the pronounced seasonal behavior across Pakistan.

Atmospheric dust is a significant air pollution problem. Particulate matter is small solid particles floating in the air. It is caused by objects that have been smashed, hit, crushed, and crushed until they break down into small parts. When blown by the wind, it will spread in the air. And fell to the ground the fall time is slow or fast depending on the dust particles' weight. Dust is divided into large dust, including small dust called PM10(dust with a diameter from 10 microns down). The stone mill problem has been a long-time problem. Many related government agencies try to fix the problem of dust pollution and health safety. PM10disperse from the source to the community nearby the stone mill was measured by the low-cost dust monitoring device. The result found that the 24-hour mean PM10particulate matter was 0.090 mg/m3, which was also lower than the statutory permissible 24-hour Mean PM10at no more than 0.12 mg/m3. The PM10dust contour map can be used for health risk management planning, primarily to mitigate the pollution to the community environment and their health under some usage limitations changes.&nbsp

Cost effective dust mitigation from surfaces is one of the challenges in various sectors. The reduction of dust adhesion on surfaces plays a vital role for dust mitigation from surfaces under the gravitational influence. Creating an avalanche effect on dusty surfaces improves the dust mitigation rate and provides an effective cleaning process. Hence, solution treatment of dust by low concentration hydrofluoric acid is considered towards reducing dust adhesion on glass surfaces. To increase the rate of dust mitigation, the avalanche influence is created by the higher density and larger size particles (5300 kg/m3 and ~ 50 µm) than the average size dust particles (2800 kg/m3 and 1.2 µm) via locating them in the top region of the dusty glass surfaces. Mitigation velocity of the dust particles is evaluated using a high-speed recording system and the tracker program. Findings revealed that solution treatment (curing) of the dust particles results in the formation of fluorine compounds, such as CaF2 and MgF2, on dust surfaces, which suppress dust adhesion on surfaces. OSHA Globally Harmonized System lists the fluorine compounds formed as environmentally non-harmful. Avalanche's influence results in dust mitigation at a smaller tilt angle of the glass surface (~ 52°) than that of the case with none-avalanche influence (63°). Area cleaned on the glass surface, via dust mitigation, is larger as the avalanche is introduced, which becomes more apparent for the solution treated dust particles. Dust mitigation under avalanche influence improves optical transmittance of the dusty glass samples by a factor of 98%.

The Landau damping of the dust ion-acoustic wave (DIAW) propagating in a dusty plasma with nonextensive distributed components is kinetically analyzed. The electron, ion, and dust particles are eff...

The leaves of C. sanguinea Pall. have the potential to accumulate dust on the surface. As the fine dust particles contain various chemical elements (ChEs), we studied the ChE composition in the leaves with different degrees of dust contamination to assess the impact on assay results. The samples of C. sanguinea leaves collected in the Kemerovo region (Russia) were divided into two groups based on the visual condition of plant material: clean leaves and dust contaminated leaves. The total ash assay revealed higher ash content, exceeding pharmacopoeial standards in the dust contaminated group. Dust contaminated leaf samples demonstrated significantly higher concentrations of many ChE: Si, Fe, Al, Na, Ti, Ni, Zr, Cr, V, Pb, La, Ga, Y, Sc and Yb comparing to non-contaminated plant material. The values of potentially hazardous ChEs were significantly lower than the maximum levels specified for medicinal raw materials in all studied samples.

We investigate the origin of the violation of the Stokes-Einstein (SE) relation in two-dimensional Yukawa liquids. Using comprehensive molecular dynamics simulations, we identify the time scales supporting the violation of the SE relation $D\propto (\eta/T)^{-1}$, where $D$ is the self-diffusion coefficient and $\eta$ is the shear viscosity. We first compute the self-intermediate scattering function $F_s(k,t)$, the non-Gaussian parameter $\alpha_2$, and the autocorrelation function of the shear stress $C_{\eta}(t)$. The timescales obtained from these functions are included the structural relaxation time $\tau_{\alpha}$, the peak time of the non-Gaussian parameter $\tau_{\alpha_2}$, and the shear stress relaxation time $\tau_{\eta}$. We find that $\tau_{\eta}$ is coupled with $D$ for all temperatures indicating the SE preservation, however, $\tau_{\alpha}$ and $\tau_{\alpha_2}$ are decoupled with $D$ at low temperatures indicating the SE violation. Surprisingly, we find that the origins of this violation are related to the non-exponential behavior of the autocorrelation function of the shear stress and non-Gaussian behavior of the distribution function of particle displacements. These results confirm dynamic heterogeneity that occurs in two-dimensional Yukawa liquids that reflects the presence of regions in which dust particles move faster than the rest when the liquid cools to below the phase transition temperature.

Trichodesmium, a globally important, N2-fixing and colony-forming cyanobacterium employs multiple pathways for acquiring nutrients from air-borne dust, including the active collection of dust particles. Once concentrated within the colony core, dust can supply Trichodesmium with the limiting nutrients iron (Fe) and phosphorus (P). Studying particle collection by natural colonies, we recently documented a preference for Fe-rich over Fe-free particles. In this follow-up study we examined if colonies selectively collect P-rich particles. Over an entire bloom season, we incubated ~1 200 Trichodesmium colonies from the Red Sea with P-free CaCO3, P-coated CaCO 3 and dust. We utilized three discrete parameters to characterize the colony-particle interactions and integrated them to an index that describes the particle collection behavior over time. Colonies were found to preferably interact, center and retain P-coated CaCO3 in comparison to P-free CaCO3, suggesting that Trichodesmium can optimize its P-acquisition by selecting P-rich particles. In both current and former studies, colonies clearly favored dust over all other particles tested, while nutrient-free particles were barely collected or retained, indicating that Trichodesmium senses the particle composition and preferably collects nutrient-rich particles. This unique ability contributes to Trichodesmium's current ecological success and may assist it to flourish in future warmer oceans.

The analytical investigation of the effect of collisions on the Jeans instability in dusty plasma is carried out to observe the effect of the simultaneous presence of polarization force and charge gradient force on the dust particles. The dispersion relation, the instability growth rate and the graphical analysis shows that the combined effect of the charge gradient force, dust polarization force and collisions moves the system towards stabilization.

The health risk of students’ exposure to some potentially toxic metals in classroom dusts in Southeast, Nigeria was assessed. Dust particles were collected from classrooms in some public high schools and digested with aqua regia before analysis for selected metals by atomic absorption spectrophotometry. The geoaccumulation index, contamination factor and the pollution load index were assessed from the metal concentrations of the dust. Hazard quotient and cancer risk index were used to estimate the potential health risk of students’ exposure to the metals in the dust. The metal concentrations (mg/kg) were in the ranges of 1.57–175.38 (Cr); 0.93–463.28 (Cu); 31.94.76–6623.41 (Fe); 4.96–143.98 (Ni); 2.64–375.27 (Zn); and 2.35–53.96 (Pb).The geo-accumulation index values showed that all the dust samples were polluted with Fe and Cr; and unpolluted with other metals with few exemptions. The contamination factor values showed that all the schools but one had a low contamination status due to Ni and Cu. There was moderate contamination by Pb at all the schools but two. All the schools had high contamination of Cr and Fe. The pollution load index indicated that the quality of all the classrooms was deteriorated. The calculated values of hazard quotient indicated that ingestion of dust at most of the classrooms would have no significant risk of non-carcinogenic effects on the health of the students. Dermal contact with the dust at all the classrooms would expose students to adverse effects of Fe. There will be adverse effect due to Pb for dermal contact with dust at most of the schools. Ingestion of dust particles at classrooms in all the schools would have carcinogenic effect due to Ni. Correlation analysis indicated that the sources of the metals varied. This study provided baseline data for relevant bodies to use in monitoring and controlling pollution so as to protect students from toxic metals.

In this work, we aim to characterize the dust motion in the inner coma of comet 67P/Churyumov-Gerasimenko to provide constraints for theoretical 3D coma models. The OSIRIS camera on-board the Rosetta mission was able for the first time to acquire images of single dust particles from inside the cometary coma, very close to the nucleus. We analyse a large number of particles, performing a significant statistic of their behaviour during the post-perihelion period, when the spacecraft covered distances from the nucleus ranging between 80 and 400 km. We describe the particle trajectories, investigating their orientation and finding highly radial motion with respect to the nucleus. Then, from the particle brightness profiles, we derive a particle rotational frequency of ν < 3.6 Hz, revealing that they are slow rotators and do not undergo fragmentation. We use scattering models to compare the observed spectral radiance of the particles with the simulated ones in order to estimate their size, finding values that range from millimetres up to centimetres. The statistics performed in this paper provide useful parameters to constrain the cometary coma dynamical models. © 2021 The Author(s)., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung in Gottingen, Germany; CISAS-University of Padova, Italy; the Laboratoire d'Astrophysique de Marseille, France; the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain; the Research and Scientic Support Department of the European Space Agency, Noordwijk, The Netherlands; the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain; the Universidad Politechnica de Madrid, Spain; the Department of Physics and Astronomy of Uppsala University, Sweden; and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universit at Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. GIADA was built by a consortium led by the Univ. Napoli Parthenope INAF-Oss. Astr. Capodimonte, in collaboration with the Inst. de Astrofisica de Andalucia, Selex-ES, FI and SENER. GIADA was managed and operated at INAF-IAPS. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with the support of the Spanish Ministry of Education and Science MEC, ES. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission. This research has been supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0, I/024/12/0, and ASI 2020-4-HH.0. Fernando Moreno acknowledges financial support from the Spanish plan National de Astrofisica y Astronomia LEONIDAS project RTI2018-095330-B-100, project P18-RT-1854 from Junta de Andalucia, and the Centro de Excelencia Severo Ochoa Program under grant SEV-2017-0709. Elisa Frattin acknowledges funding from Italian Ministry of Education, University and Research (MIUR) through the `Dipartimenti di eccellenza' project Science of the Universe.

Recent observations of extrasolar gas giants suggest super-stellar C/O ratios in planetary atmospheres, while interior models of observed extrasolar giant planets additionally suggest high heavy element contents. Furthermore, recent observations of protoplanetary disks revealed super-solar C/H ratios, which are explained by inward drifting and evaporating pebbles, enhancing the volatile content of the disk. We investigate how the inward drift and evaporation of volatile rich pebbles influences the atmospheric C/O ratio and heavy element content of giant planets growing by pebble and gas accretion. To achieve this goal, we perform semi analytical 1D models of protoplanetary disks including the treatment of viscous evolution and heating, pebble drift and simple chemistry to simulate the growth of planets from planetary embryos to Jupiter mass objects by accretion of pebbles and gas while they migrate through the disk. Our simulations show that the composition of the planetary gas atmosphere is dominated by the accretion of vapour, originating from inward drifting evaporating pebbles. This process allows the giant planets to harbour large heavy element contents. In addition, our model reveals that giant planets originating further away from the central star have a higher C/O ratio on average due to the evaporation of methane rich pebbles in the outer disk. These planets can then also harbour super-solar C/O ratios, in line with exoplanet observations. However, planets formed in the outer disk harbour a smaller heavy element content, due to a smaller vapour enrichment of the outer disk. Our model predicts that giant planets with low/large atmospheric C/O should harbour a large/low total heavy element content. We further conclude that the inclusion of pebble evaporation at evaporation lines is a key ingredient to determine the heavy element content and composition of giant planets., accepted for publication in A&A

The presence of dust in the interstellar medium was highlighted by Trumpler who, in an investigation of the diameters of Galactic clusters, found a poorly convincing result: their diameters were an increasing function of distance. The origin of this result was linked to the determination of the distances made with photometry, a distance that was overestimated precisely for the absorbing action of solid dust particles. The study of the spatial distribution of these led to the conclusion that dust was associated with the interstellar gas.

Machining of composite creates dust particles that can enter the human respiratory system and reach the bloodstream. Several toxicology studies depict the harmful effect of composite dust on animals. This chapter briefly reviews the detrimental impacts of composite dust, exposure limit of dust, and methods to collect and control dust generation. The relationship of machining parameters to dust formation is discussed based on the limited existing literature. A safe dust collection and real-time dust analysis system based on the isokinetic sampling technique is illustrated in this chapter.

We investigate Fickian diffusion in two-dimensional (2D) Yukawa liquids using molecular dynamics simulations. We compute the self-van Hove correlation function G_{s}(r,t) and the self-intermediate scattering function F_{s}(k,t), and we compare these functions with those obtained from mean-squared displacement (MSD) using the Gaussian approximation. According to this approximation, a linear MSD with time implies a Gaussian behavior for G_{s}(r,t) and F_{s}(k,t) at all times. Surprisingly, we find that these functions deviate from Gaussian at intermediate timescales, indicating the failure of the Gaussian approximation. Furthermore, we quantify these deviations by the non-Gaussian parameter, and we find that the deviations increase when the temperature of the liquid decreases. The origin of the non-Gaussian behavior may be the heterogeneous dynamics of dust particles observed in 2D Yukawa liquids.

We present a novel mechanism for the outward transport of crystalline dust particles: the outward radial drift of pebbles. The dust ring structure is frequently observed in protoplanetary disks. One of the plausible mechanisms of the formation of dust rings is the accumulation of pebbles around the pressure maximum, which is formed by the mass loss due to magnetically driven disk winds. In evolving protoplanetary disks due to magnetically driven disk winds, dust particles can migrate outwardly from the crystallization front to the pressure maximum by radial drift. We found that the outward radial drift process can transport crystalline dust particles efficiently when the radial drift timescale is shorter than the advection timescale. Our model predicts that the crystallinity of silicate dust particles could be as high as 100% inside the dust ring position., Comment: 15 pages, 14 figures. Accepted for publication in ApJ

As dust particles in laying poultry houses can have negative effects on health and on the environment, this study aimed to measure and compare dust concentrations in egg production sheds. The experiment was carried out in three sheds: Californian shed (G1), conventional closed shed with artificial ventilation (G2) and conventional closed shed without artificial ventilation (G3), and the birds housed were in the 22nd week of housing, in Cuité, Paraíba, Brazil. The dust particles were collected by a gravimetric pump, attached to the workers’ clothes, at the height of the respiratory zone, being removed at the end of the working day. Using the evaluation methodologies (total or breathable dust) according to NIOSH (1998), weighing was performed with sample concentration calculation, then the particle size was measured by microscopy according to the methodology described by Feret (Santos, 2001), with diameter of function obtained using an optical microscope, and particles classified by size (inhalable

Particulate matter is a concern and a consequence of the rapid urbanization. These particulate matters of size less than 15 μm are a major deteriorator of public health and wellbeing. Particles size less than 10 microns reach respiratory track and particles size less than 2.5 μm can reach the bronchioles of lungs. Lack of dust management at construction sites may lead to wide spread chronic health diseases linked to non-fatal heart attacks, irregular heartbeat, aggravated asthma, silicosis, lung cancer etc. Average life expectancy of people continuously exposed to Total Suspended Particulates (TSP) reduces over a period of time. A construction site where various activities carried out produces a significant amount of dust particles hence effective management of those particulate matters are of great importance. This paper discusses on the Dust management aspects for the control of total suspended particulate matter generated at a High-rise building construction site. Sampling was carried out using particulate matter measuring equipment and real time monitors. Results were compared with national ambient air quality standards and suggestive measures are proposed for effective dust management in construction sites.

Brunauer, Emmett, and Teller (BET) test were applied to dust samples in which samples (BET) surface area is highly related to the roundness of dust particles. The higher angularity and low roundness of the dust particles show a higher (BET) surface area. The roundness is also related to the particlesize distribution and mineralogical composition. The electrical conductivity test relates very well with the chemical and physical properties of dust samples in the transmission of an electrical current. The organic matter content was measured using the ignition method and the pH of the samples was recorded. Maps of the distribution of high and low BET concentrations, electrical conductivity EC, organic matter content, pH.

Soiling consists of the accumulation of dust on the solar panel's surface and has a deleterious effect on solar photovoltaic devices' performance, which varies with location. However, soiling losses and rates are significantly under-reported or underestimated since regional differences and seasonal variations are overlooked. Accurate prediction of PV soiling losses for a particular location can save revenue losses associated with a solar PV system. This research investigated the effect of soiling on PV performance through optical losses by employing a low-cost soiling station. Low iron glass coupons (5 mm × 5 mm) were exposed on three angles (vertical, tilt-45°, and horizontal) in seven sites across Nigeria to collect annual, seasonal and monthly soiling data. Each coupon was then subjected to optical characterisation using a spectrometer and imaging analysis using the SEM/EDX. The finding shows significant optical losses across the country, with all the highest rates recorded on coupons exposed on the horizontal plane, where the maximum loss of 88% was recorded on the Abuja, North Central (ABV) coupon. SEM/EDX finding illustrated minerals with the potential to affect light transmittance, and the pollutant data confirmed the particles. The optical results were further employed to map the soiling distribution across the country. A wide deviation was observed from the data on the Global Solar Atlas, as it disproportionately underestimated the soiling losses across the world.

The properties (densities of electrons and metastable argon atoms, effective electron temperature and dust charge) of argon/dust and pure argon pulsed plasmas are studied using a spatially-averaged model. The calculated time-dependencies for the densities of electrons and metastable atoms are compared with the experimental measurements and are found to be in a good qualitative agreement. It is analyzed how the plasma properties depend on the shape of the electron energy probability function (EEPF), the pulsing frequency and the duty cycle for both dust-free and dusty plasma. The analysis reveals that the agreement between theory and experiment is better with Druyvesteyn EEPF than the Maxwellian EEPF. Further, the variation in the pulsing frequency νp differently affects the metastable density nm in a dust-free and in a dusty plasma. For large νp, the metastable density in the dust-free pulsed plasma is larger than in the continuous-wave (CW) discharge, while the opposite is obtained in the presence of dust particles. This difference probably arises because of faster variation in the effective electron temperature in the dusty plasma due to collection of electrons by dust particles. Our calculations also show that dust particles may affect the behavior of electron density in the beginning of the on-period due to an enhancement in electron collection by dust particles. This is the peer-reviewed version of the article: Denysenko I. B., Stefanović Ilija, Mikikian M., Kovačević E., Berndt J., "Argon/dust and pure argon pulsed plasmas explored using a spatially-averaged model" Journal of Physics D: Applied Physics, 54, no. 6 (2021):065202, [https://doi.org/10.1088/1361-6463/abc210]. Published version: [https://hdl.handle.net/21.15107/rcub_dais_9988]

Agricultural fires affecting grass-, crop- and shrublands represent a major, mainly anthropogenically driven disturbance of many ecosystems. In addition to emissions of carbonaceous aerosol, they were found to inject also mineral dust particles into the atmosphere. The fires can significantly modulate the near-surface wind patterns so that conditions suitable for dust emission occur. However, the exact emission mechanism has not been investigated so far, but is inevitable for the understanding of its impacts on the Earth system. Here, we test two dust emission parameterizations representing saltation bombardment (SALT) and direct aerodynamic dust entrainment by (convective) turbulence (convective turbulent dust emission, CTDE) in the context of fire-modulated wind patterns using large-eddy simulation with an idealized setup to represent typical agricultural fire settings. Favorable aerodynamic preconditions for the initialization of both emission processes are found, however, with sometimes significant differences in dust emission flux depending on specific wind and fire properties. The strong fire-induced modulations of the instantaneous momentum flux suggest that CTDE can be a very potent emission process in the fire vicinity. Nevertheless, fire impacts on the friction velocity can be significant too, so that dust emission through SALT is facilitated as well. Ultimately, the specific aerodynamic conditions within pyro-convectively modulated wind patterns require the development of a parameterization that can describe these unique fire-related dust emissions and their influencing factors properly. This will finally allow for considering fire-induced dust emissions in aerosol-atmosphere models and an investigation of its atmospheric impacts such as on the radiation budget. R. Wagner and K. Schepanski thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for funding the project SCHE 1678/5–1. M. Klose has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 789630 and from the Helmholtz Association's Initiative and Networking Fund (grant agreement no. VH-NG-1533). The authors acknowledge the Center for Information Services and High performance Computing (ZIH) of the Technische Universität Dresden (TU Dresden) for providing computing capacity. The authors are grateful to the three anonymous reviewers for their valuable comments and suggestions that helped to improved the quality of the paper.

Dust accumulation on photovoltaic (PV) modules causes a significant reduction in the electrical energy output by partially blocking the solar irradiance incident on the PV modules. The effect is more pronounced during the dry season when the environment is dustier. In this work, an investigation is conducted to understand how dust particles can affect the performance of the PV panels installed on the rooftop of a high-rise building during the dry season. Two monocrystalline 20W PV panels, deployed on the rooftop of a seven-story building in Gabtoli, Dhaka, Bangladesh, have been used for this purpose. Measurements are carried out over four months, starting from 1st November 2019 to 29th February 2020, during which the weather remains mostly cold, dry, and dusty. It has been observed that dust accumulation monthly decreases the short-circuit current from a minimum of 5.52% to a maximum of 22.31% during this period. The maximum reduction in the daily output energy during this period is observed to be about 35%. The effect of dust has been observed to be most pronounced during December 2019, which shows a decrease of over 22% in total monthly energy output in the dusty panel compared to that of the clean panel.

We have measured artificial radionuclides, such as 90Sr and 137Cs, in atmospheric depositions since 1957 in Japan. We observed the variations in 90Sr and 137Cs, which were emitted from atmospheric nuclear tests and nuclear power plant accidents, due to their diffusion, deposition, and resuspension. In March 2011, the Fukushima Daiichi Nuclear Power Plant accident occurred in Japan, and significant increases in 90Sr and 137Cs were detected at our main site in Tsukuba, Ibaraki. Our continual observations revealed that the 137Cs monthly deposition rate in 2018 declined to ~ 1/8100 of the peak level, but it remained more than ~ 400 times higher than that before the accident. Chemical analysis suggested that dust particles were the major carriers of 90Sr and 137Cs during the resuspension period at our main site. Presently, the effective half-life for 137Cs deposition due to radioactive decay and other environmental factors is 4.7 years. The estimation suggests that approximately 42 years from 2011 are required to reduce the atmospheric 137Cs deposition to a state similar to that before the accident. The current 90Sr deposition, on the other hand, shows the preaccident seasonal variation, and it has returned to the same radioactive level as that before the accident.

An in-situ cosmic-dust instrument called the Mercury Dust Monitor (MDM) had been developed as a part of the science payload for the Mio (Mercury Magnetospheric Orbiter, MMO) stage of the joint European Space Agency (ESA)–JAXA Mercury-exploration mission. The BepiColombo spacecraft was successfully launched by an Ariane 5 rocket on October 20, 2018, and commissioning tests of the science payload were successfully completed in near-earth orbit before injection into a long journey to Mercury. MDM has a sensor consisting of four plates of piezoelectric lead zirconate titanate (PZT), which converts the mechanical stress (or strain) induced by dust-particle impacts into electrical signals. After the commencement of scientific operations, MDM will measure the impact momentum at which dust particles in orbit around the Sun collide with the sensor and record the arrival direction. This paper provides basic information concerning the MDM instrument and its predicted scientific operation as a future reference for scientific articles concerning the MDM’s observational data.

Particulate air components can be of anthropogenic or natural origin. It is assumed that in different geographical areas varying concentrations of mesophilic bacteria are present in the ambient air. The aim of this study was to determine the background concentrations of airborne culturable mesophilic bacteria and particulate matter in the ambient air. Furthermore, the association between their concentrations and some environmental factors was analysed. In the period from July to October 2019, concentrations of mesophilic bacteria and dust particles were measured in urban, rural and mountain areas using the single-stage air sampler and the particle counter. The concentrations of bacteria and dust particles in the air were counted as number of Colony Forming Units per cubic metre (CFU/m3) and particles per cubic metre (pa/m3). Staphylococcus sp. were identified. The median values of the cultivated mesophilic bacteria at 30 &deg, C and 37 &deg, C were 7.1 &times, 102 CFU/m3 and 2.3 &times, 101 CFU/m3 in mountain regions, 1.3 &times, 102 CFU/m3 and 6.9 &times, 101 CFU/m3 in rural regions and 2.1 &times, 102 CFU/m3 and 6.5 &times, 101 CFU/m3 in urban regions. The median of Staphylococcus sp. was 2.5 &times, 100 CFU/m3 in alpine areas and 7.5 &times, 100 CFU/m3 in urban and rural areas. Higher bacterial concentrations were measured in sunshine and in windy weather. A relationship was observed between the concentrations of airborne mesophilic bacteria and the coarse particles in all three areas. The present study determined values between 5.0 &times, 100 and 4.6 &times, 102 CFU/m3 as natural background concentrations of airborne mesophilic bacteria and 1.2 &times, 107 pa/m3 and 6.5 &times, 104 pa/m3 for fine and coarse particles, respectively. These results can be proposed as baseline for the assessment of the emission sources of mesophilic bacteria for summer and early autumn.

Naegleria fowleri is a free-living protozoan that resides in soil and freshwater. Human intranasal amoebae exposure through water or potentially dust particles can culminate in primary amoebic meningoencephalitis, which generally causes death. While many questions remain regarding pathogenesis, the microbial ecology of N. fowleri is even less understood. This review outlines current knowledge of the environmental abiotic and biotic factors that affect the distribution and abundance of N. fowleri. Although the impacts of some abiotic factors remain poorly investigated or inconclusive, N. fowleri appears to have a wide pH range, low salinity tolerance and thermophilic preference. From what is known about biotic factors, the amoebae preferentially feed upon bacteria and are preyed upon by other free-living amoebae. Additional laboratory and environmental studies are needed to fill in knowledge gaps, which are crucial for surveillance and management of N. fowleri in freshwaters. As surface water temperatures increase with climate change, it is likely that this amoeba will pose a greater threat to human health, suggesting that identifying its abiotic and biotic preferences is critical to mitigating this risk., Naegleria fowleri, the so-called brain-eating amoeba, is thermophilic, suggesting that its occurrence will increase with climate change, highlighting the need to better understand which abiotic and biotic factors influence its distribution and abundance.

Machining of CFRP composite creates many kinds of induced damage like delamination, fiber pullout, etc. these kinds of damage strongly are associated with appearance of dust generated during machining. The small dust particles can be inhaled by operators in machining areas, which can make them get some diseases. However, there have been few studies dealing with this problem. This study aims to investigate the influences of cutting parameters (cutting speed, feed speed and depth of cut) on the number and mass of thoracic which possess aerodynamic diameter particles lower than 32 µm. Dust particles were collected using a dust monitor. The results show that when cutting speed increases the number of thoracic particles increases. Moreover, an increase of feed speed or depth of cutting leads to reduce the number and mass of thoracic particles.

This study reports seasonal variations of meteorological parameters, atmospheric dust and dust-borne heavy metals concentrations measured, over a period of two years, next to two major airports (Dubai International Airport and Abu Dhabi International Airport) in the Gulf Cooperation Council (GCC) region. On-line monitoring stations were installed at each location next to dust samplers used to frequently collect PM2.5 and PM10 on Teflon filters for metal analysis. Clear seasonal variation in meteorological parameters were identified. The particulate matter concentrations depicted from the two locations were continuously monitored. The PM2.5 concentration ranged from 50 to 100 μg/m3 on normal days but reached 350–400 μg/m3 per day during mild storms. The PM10 levels ranged between 100 and 250 μg/m3 during normal days and spiked to 750 μg/m3 during mild storms. Energy Dispersive X-Ray Analysis (EDS) revealed the presence of significant amounts of alkali and alkaline earth metals, which pose potential harm to aircraft engines. ICP analysis showed the presence of heavy and toxic metals in concentrations that may pose harm to human health. Bulk sand samples from Abu Dhabi sites showed chemical similarities to the atmospheric dust samples. The concentrations of heavy metals, PM2.5, and PM10 are at levels that require further monitoring due to their impact on human health. The two years meteorological monitoring, with the seasonal variations, provided additional regional data in the Arabian Gulf. Furthermore, the study concluded that Sand and Dust storms (SDS) occur more frequently at the northern Arabian Gulf compared to its southern region. The chemical correlation between atmospheric dust and regional desert sand suggests the localized origin of the smaller dust particles that may form by breaking apart of the ground sand grains. As a result of the ongoing urbanization in the region, it is essential to collect additional data from various locations for a longer period of time.

A robust impurity detection and tracking code, able to generate large sets of dust tracks from tokamak camera footage, is presented. This machine learning-based code is tested with cameras from the Joint European Torus, Doublet-III-D, and Magnum-PSI and is able to generate dust tracks with a 65-100% classification accuracy. Moreover, the number dust particles detected from a single camera shot can be up to the order of 1000. Several areas of improvement for the code are highlighted, such as generating more significant training data sets and accounting for selection biases. Although the code is tested with dust in single two-dimensional camera views, it could easily be applied to multiple-camera stereoscopic reconstruction or nondust impurities.