Dust Density Research Articles

Comprehensive performance analysis of a rural building integrated PV/T wall in hot summer and cold winter region

The building-integrated PV/T technologies have garnered significant attention due to their considerable potential in low-carbon and zero-energy buildings. To gain deeper insights into the practical application of this technology, a comprehensive study was conducted on a rural building integrated with PV/T walls for demonstration purposes. A novel simulation approach, coupling the numerical models of the PV/T walls with the building energy software, was proposed and experimentally validated. Based on the validated simulation approach, this study investigated the comprehensive performance of the demo building and explored the optimal capacity of the energy storage system (ESS). The main findings are as follows: (1) The proposed simulation approach could accurately predict the energy behaviors of the multi-room building integrated PV/T wall. (2) The demo building with the optimized EES yielded 1355.32 kWh of clean electricity and 455.3 kWh of heat gain for water heating, while reducing cooling and heating loads by 5% and 12%, respectively. (3) The optimal azimuth for the building in the studied region was 45°, and the total energy benefits of the building decreased by 28.5% with an increase in dust density from 0 g/m2 to 10 g/m2.

Wave breaking amplitudes of Langmuir modes in electron-positron-ion-dusty plasmas

In contrast to the conventional studies on low frequency dust acoustic or dust ion acoustic waves, the investigation is done here on the wave characteristics of high frequency Langmuir modes in electron-positron-ion-dusty plasmas. In the wave analysis, the electrons, positrons, and ions are considered to follow relativistic dynamics. Whereas negative or positive polarity massive dust grains form a fixed charge neutralizing background. Within the Sagdeev pseudopotential approach, the wave breaking amplitudes of such high frequency oscillations are derived. The wave breaking amplitudes are shown to depend on various system parameters like equilibrium ion-to-electron density ratio, relativistic Lorentz factor associated with the phase velocity of oscillations, etc. It has been demonstrated that, even though the dust grains do not participate in the wave dynamics, the nature of their charge polarity and the values of equilibrium dust density have profound effects on the wave breaking amplitudes. We expect that the results of our investigation in such dusty plasma medium may have some relevance in the space plasma research.

A panoptic view of the Taurus molecular cloud

We present a study of the three-dimensional (3D) distribution of interstellar dust derived from stellar extinction observations toward the Taurus molecular cloud (MC) and its relation with the neutral atomic hydrogen (H I) emission at 21 cm wavelength and the carbon monoxide 12CO and 13CO emission in the J = 1 → 0 transition. We used the histogram of oriented gradients (HOG) method to match the morphology in a 3D reconstruction of the dust density (3D dust) and the distribution of the gas tracers’ emission. The result of the HOG analysis is a map of the relationship between the distances and radial velocities. The HOG comparison between the 3D dust and the H I emission indicates a morphological match at the distance of Taurus but an anticorrelation between the dust density and the H I emission, which uncovers a significant amount of cold H I within the Taurus MC. The HOG study between the 3D dust and 12CO reveals a pattern in radial velocities and distances that is consistent with converging motions of the gas in the Taurus MC, with the near side of the cloud moving at higher velocities and the far side moving at lower velocities. This convergence of flows is likely triggered by the large-scale gas compression caused by the interaction of the Local Bubble and the Per-Tau shell, with Taurus lying at the intersection of the two bubble surfaces.

Propagation characteristics of dust density waves in an external magnetic field

Propagation of dust density waves (DDW) is theoretically investigated in a collisional plasma in the presence of an external magnetic field. The magnetic field is kept constant in a direction perpendicular to the direction of streaming ions, which is an important requirement for the self-excitation of these waves. Standard stability analysis is done to predict the conditions under which ion-drift instability may drive the DDW unstable. It is found that a minimum dust density is required to excite the wave. There exists a lower cut-off value of ion streaming velocity for the excitation of DDW which may change with the applied magnetic field and neutral gas pressure. The wave is found to behave complexly with the applied magnetic field and gets damped beyond a critical value. The results of this paper may be helpful in understanding the behavior of low-frequency dust modes as well as the background plasma both in laboratory and astrophysical environments.

Dust density effects on electron density gradient driven lower hybrid waves in magnetized plasma

AbstractElectrostatic lower hybrid waves propagating transverse to the external magnetic field in magnetized dusty plasma are investigated, using the fluid equations and also including the effect of density gradient in plasma. Lower hybrid modes are considered important in laboratory, astrophysical as well as space plasmas in interpreting low frequency noises. Unlike other electrostatic waves, lower hybrid waves can resonantly interact with electrons as well as ions in plasma. The dust and gradient terms lead to novel growth of these waves in dusty plasma. A theoretical model is developed to investigate density gradient effects on lower hybrid waves in plasma comprised of electrons, ions and dust particles. The dependence of plasma components' density, strength of magnetic field, temperature and charge of electrons, ions and dust grains on the frequency and growth rate of electrostatic lower hybrid waves has been investigated and presented graphically. It has been observed that the number density of each plasma components directly affects the growth rate. The electrostatic waves are found to grow along the positive electron gradient and the dust effect depends on the gradient length chosen. Above a certain threshold value of gradient length, the waves are found to stabilize. A correlation of the obtained theoretical results with the experimental observations is also discussed.

Rancang dan Bangun Sistem Pembersih Permukaan Panel Surya Otomatis dengan Sistem Elektromekanis Cerdas

The influence of weather changes on the cleanliness of solar panel surfaces is a problem that must be faced at this time. One of the factors that can affect the output value of roof photovoltaic efficiency is the level of dust density found on the photovoltaic surface. Solutions that can be used as a panel surface cleaner can use an automatic cleaning system to overcome the amount of dust on the photovoltaic surface. The method used in this study uses the Arduino Amega328p component, GP2Y1010AU0F sensor, Arduino drive, and real-time testing. There is a dust sensor and a voltage sensor to determine the amount of dust density on the photovoltaic surface, while the voltage sensor can be used as a reader of the voltage output on the photovoltaic. This research aims to help humans work in cleaning rooftop solar panels and create a system for detecting the thickness of dust and dust cleaners to increase the efficiency value of solar panels from solar radiation absorbed on the surface. The results of the PWM research with a duty cycle of 100% Vout 11.72 Volts, Dust Density of 0.54 mg/m3 produce analog data of 3.75 Volts and an ADC value of 767. Meanwhile, an analog sensor value is obtained for a dust density of 0.41 mg/m3d. of 3.02 Volts, logic 1 and the cleaning actuator ON position. Surface conditions and abnormal conditions are dusty at 0.54 mg/m3 for photovoltaic sensors at 9.13. The resulting efficiency when the photovoltaic surface is clean is 55%-80%.

Effect of Fe2O3 Nanoparticles Dust on the D.C Plasma Characteristics with Mirror Magnetron

In this paper, the effect of iron oxide nanoparticles dust (Fe2O3 NPs) on the parameters of DC electric discharge plasma under vacuum in argon gas was studied with the presence of a mirror magnetron behind the electrodes (cathode and anode) at constant pressure and with different amounts of Fe2O3 nanoparticles. Calculations presented a reduction of the plasma emission intensity with the NPs content. Both the plasma density (calculated by Stark's broadening method) and the mean electron temperature (calculated using Boltzmann's equation) decreased with increasing the Fe2O3 nanoparticles dust content, which indicates clearly the effect of dust density on restricting the movement of charge carriers, which in turn reduces inelastic plasma collisions.

Simulation of DC glow discharge plasma with free-moving dust particles in the radial direction

A self-consistent fluid model is developed to investigate the radial distributions of dusty plasma parameters in a DC glow discharge, in which the extended fluid approach of plasma particles and the transport equations of dust particles are coupled. The electrical interaction between charged dust particles is considered in the model. The time evolution of radial distributions of dust density, plasma density, the radial component of electric field and the forces acting on dust particles when dust density tends to be stable, are obtained and analyzed under different discharge currents and dust particle radii. It is shown that the dust density structure is determined mainly by the radial electrostatic force, thermophoretic force and ion drag force in the discharge tube, and both discharge current and dust particle radius have an obvious effect on the transport processes of dust particles. The dust particles gather in the central region of the discharge tube for low discharge current and small dust radius, then dust voids are formed and become wider when the discharge current and dust radius increase. The plasma parameters in the dust gathering region are obviously affected by the dust particles due to the charging processes of electrons and ions to the dust surface.

Observability of photoevaporation signatures in the dust continuum emission of transition discs

ABSTRACT Photoevaporative disc winds play a key role in our understanding of circumstellar disc evolution, especially in the final stages, and they might affect the planet formation process and the final location of planets. The study of transition discs (i.e. discs with a central dust cavity) is central for our understanding of the photoevaporation process and disc dispersal. However, we need to distinguish cavities created by photoevaporation from those created by giant planets. Theoretical models are necessary to identify possible observational signatures of the two different processes, and models to find the differences between the two processes are still lacking. In this paper, we study a sample of transition discs obtained from radiation–hydrodynamic simulations of internally photoevaporated discs, and focus on the dust dynamics relevant for current Atacama Large Millimetre Array observations. We then compared our results with gaps opened by a super-Earth/giant planets, finding that the photoevaporated cavity steepness depends mildly on gap size, and it is similar to that of a ${1}\, {\rm M_J}$ planet. However, the dust density drops less rapidly inside the photoevaporated cavity compared to the planetary case due to the less efficient dust filtering. This effect is visible in the resulting spectral index, which shows a larger spectral index at the cavity edge and a shallower increase inside it with respect to the planetary case. The combination of cavity steepness and spectral index might reveal the true nature of transition discs.

A Bayesian chemical evolution model of the DustPedia galaxy M74

ABSTRACT We introduce a new, multizone chemical evolution model of the DustPedia galaxy M74, calibrated by means of Markov Chain Monte Carlo methods. We take into account the observed stellar and gas density profiles and use Bayesian analysis to constrain two fundamental parameters characterizing the gas accretion and star formation time-scale, i.e. the infall time-scale τ and the SF efficiency ν, respectively, as a function of galactocentric radius R. Our analysis supports an infall time-scale increasing with R and a star formation efficiency decreasing with R, thus supporting an ‘Inside-Out’ formation for M74. For both τ and ν, we find a weaker radial dependence than in the Milky Way. We also investigate the dust content of M74, comparing the observed dust density profile with the results of our chemical evolution models. Various prescriptions have been considered for two key parameters, i.e. the typical dust accretion time-scale τ0 and the mass of gas cleared out of dust by a supernova remnant, Mclear, regulating the dust growth and destruction rate, respectively. Two models with a different current balance between destruction and accretion, i.e. with an equilibrium and a dominion of accretion over destruction, can equally reproduce the observed dust profile of M74. This outlines the degeneracy between these parameters in shaping the interstellar dust content in galaxies. Our methods will be extended to more DustPedia galaxies to shed more light on the relative roles of dust production and destruction.

Inner edges of planetesimal belts: collisionally eroded or truncated?

ABSTRACT The radial structure of debris discs can encode important information about their dynamical and collisional history. In this paper, we present a three-phase analytical model to analyse the collisional evolution of solids in debris discs, focusing on their joint radial and temporal dependence. Consistent with previous models, we find that as the largest planetesimals reach collisional equilibrium in the inner regions, the surface density of dust and solids becomes proportional to ∼r2 within a certain critical radius. We present simple equations to estimate the critical radius and surface density of dust as a function of the maximum planetesimal size and initial surface density in solids (and vice versa). We apply this model to Atacama Large Millimeter/submillimeter Array observations of seven wide debris discs. We use both parametric and non-parametric modelling to test if their inner edges are shallow and consistent with collisional evolution. We find that four out of seven have inner edges consistent with collisional evolution. Three of these would require small maximum planetesimal sizes below 10 km, with HR 8799’s disc potentially lacking solids larger than a few centimetres. The remaining systems have inner edges that are much sharper, which requires maximum planetesimal sizes ≳ 10 km. Their sharp inner edges suggest they could have been truncated by planets, which JWST could detect. In the context of our model, we find that the seven discs require surface densities below a Minimum Mass Solar Nebula, avoiding the so-called disc mass problem. Finally, during the modelling of HD 107146 we discover that its wide gap is split into two narrower ones, which could be due to two low-mass planets formed within the disc.

Experimental investigation of a monitoring model for dust deposition on solar photovoltaic modules

ABSTRACT Accurately evaluating dust deposition characteristics on photovoltaic modules is vital for improving power generation prediction and formulating cleaning cycles. This study analyzed the composition and size characteristics of dust collected from a solar photovoltaic power station in the Kubuqi Desert. Relationships were established among dust density, solar cell output parameters, actual radiation intensity, and spectral transmittance through experiments. Based on this, a monitoring model for dust deposition on PV modules was proposed and validated in the laboratory. Results showed that the composition and particle size of dust deposited on PV modules did not significantly differ across various areas of the station.Under the same dust deposited density, spectral transmittance exponentially decayed with increased dust density, with shorter wavelengths being more affected. Operating current loss accurately reflected dust deposition compared to other output parameters. The proposed monitoring model achieved 94% accuracy in reflecting the degree of dust deposition. This study provides theoretical support for intelligent operation schemes of solar PV power generation stations.

Nonlinear pulsational mode dynamics in strongly correlated dust molecular clouds

We theoretically study the nonlinear pulsational mode dynamics in strongly correlated (viscoelastic) self-gravitating complex charge-fluctuating dust molecular clouds (DMCs) on the astrophysical spatiotemporal scales. A nonlinear normal mode (local) analysis results in a unique pair of extended Kortweg de-Vries-Burgers (KdV-B) equations on the conjugational gravito-electrostatic potential fluctuations in a mixed form. The KdV-B system is numerically analysed in a wide-range parametric window relevant to realistic astronomical DMC circumstances. It is found that the fluctuation dynamics evolves as solitary-chain patterns. The electrostatic fluctuation amplitude increases with the referral frame velocity; whereas, the gravitational fluctuations are insensitive to this velocity. The fluctuation dynamics are found to be independent of variation in the equilibrium dust density, equilibrium dust charge, dust mass, and so forth. The validation and reliability checkup of our results is highlighted in fair corroboration with the literature. Our results could be useful in understanding the mechanism behind bounded structure formation via the non-local self gravitational collapse dynamics.

Iceline variations driven by protoplanetary disc gaps

ABSTRACT The composition of forming planets is strongly affected by the protoplanetary disc’s thermal structure. This thermal structure is predominantly set by dust radiative transfer and viscous (accretional) heating and can be impacted by gaps – regions of low dust and gas density that can occur when planets form. The effect of variations in dust surface density on disc temperature has been poorly understood to date. In this work, we use the radiative transfer code MCMax to model the 2D dust thermal structure with individual gaps corresponding to planets with masses of 0.1 MJ –5 MJ and orbital radii of 3, 5, and 10 au. Low dust opacity in the gap allows radiation to penetrate deeper and warm the mid-plane by up to 16 K, but only for gaps located in the region of the disc where stellar irradiation is the dominant source of heating. In viscously heated regions, the mid-plane of the gap is relatively cooler by up to 100 K. Outside of the gap, broad radial oscillations in heating and cooling are present due to disc flaring. These thermal features affect local dust–gas segregation of volatile elements (H2O, CH4, CO2, and CO). We find that icelines experience dramatic shifts relative to gapless models: up to 6.5 au (or 71 per cent) closer to the star and 4.3 au (or 100 per cent) closer to the mid-plane. While quantitative predictions of iceline deviations will require more sophisticated models, which include transport, sublimation/condensation kinetics, and gas–dust thermal decoupling in the disc atmosphere, our results suggest that planet-induced iceline variations represent a potential feedback from the planet on to the composition of material it is accreting.

Measurement of Fine/Ultrafine Dust Using Lenticular Fiber-Based Particulate Measurement Devices

Measurement of particulate matter (PM), i.e., fine/ultrafine dust, is important for monitoring our surrounding environment. We demonstrate the fabrication of lenticular fiber-based fine/ultrafine dust measurement devices for monitoring the density and size of dust. The plano-convex lenticular fibers were fabricated by the CO2 laser polishing technique. The optical lens, used in the conventional light scattering-based fine/ultrafine dust measurement devices, was replaced by a plano-convex lenticular optical fiber to reduce the size and complexity of the dust measurement device. We utilized a light-emitting diode as the light source of the fine/ultrafine dust density measurement device. The fabricated device could indicate the dust density level (good, normal, bad, and very bad) according to the Korean standard. To estimate the size of the dust particulates, we fabricated a dust size measurement device that consists of a compact laser diode, a lenticular fiber, and a photodetector. We are successful in estimating the size of both fine and ultrafine PMs by detecting the power of the scattered light coming from the dust particulates. The dust size down to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.9 \mu \text{m}$ </tex-math></inline-formula> was detected using our dust measurement device. Our proposed dust measurement devices are simple, small, and cost-effective and can be considered as a candidate for portable applications.

Kinematics signature of a giant planet in the disk of AS 209

Observations of dust in protoplanetary disks with the Atacama Large Millimeter Array (ALMA) are revealing the existence of substructures such as rings, gaps, and cavities. This morphology is expected to be the outcome of dynamical interaction between the disks and (embedded) planets. However, other mechanisms are able to produce similar dust substructures. A solution to discriminate the gap formation mechanism is to look at the perturbation induced by the planet on the gas surface density and/or the kinematics. In the case of the disk around AS 209, a prominent gap has been reported in the surface density of CO atr ~100 au. A further gas gap was identified atr~ 200 au. Recently, a localized velocity perturbation was reported in the12COJ= 2−1 emission along with a clump in13COJ= 2−1 at nearly 200 au and this was interpreted as a gaseous circumplanetary disk. In this paper, we report a new analysis of ALMA archival observations of12CO and13COJ= 2−1 in AS 209. We detected a clear kinematics perturbation (kink) in multiple channels and over a wide azimuth range in both datasets. We compared the observed perturbation with a semianalytic model of velocity perturbations due to planet-disk interaction. Based on our analysis, the observed kink is not consistent with a planet at 200 au, as this would require a low gas-disk scale height (&lt;0.05) in contradiction with the previous estimate (h/r ~0.118 atr= 100 au). When we fix the disk scale height to 0.118 (atr= 100 au), we find instead that a planet at 100 au induces a kinematics perturbation similar to the one observed. The kink amplitude in the various channels implies a planet mass of 3–5MJup. Thus, we conclude that a giant proto-planet orbiting atr~ 100 au is responsible for the large-scale kink as well as for the perturbed dust and gas surface density previously detected. The position angle of the planet is constrained to be between 60° and 100° (east of north). The 200 au gap visible in the12COJ= 2−1 moment zero map is likely due to density fluctuations induced by the spiral wake. Future observations using the high-contrast imaging technique in the near- and mid-infrared (e.g., with JWST and/or VLT/ERIS) are needed to confirm the presence and position of such a planet.

Comparison of the Eulerian and Lagrangian Approaches to Studying the Peculiarities of the Interstellar Dust Distribution in the Heliosphere in the Framework of the Cold Gas Model

Interstellar dust grains penetrate into the heliosphere (region in which the solar wind propagates) due to the relative motion of the Sun and the Local Interstellar Medium (LISM). Inside the heliosphere, the motion of dust particles is mainly governed by the electromagnetic force determined by the heliospheric magnetic field. Under the action of this force, the trajectories of dust grains experience intersections with each other and self-intersections. As a result, dust density accumulation regions appear. These regions are of a great interest in the context of theoretical studying and planning of upcoming space missions. The main aim of the present study is to model the interstellar dust distribution in the heliosphere and investigate the peculiarities of the number density distribution. To describe the dusty component, the cold gas model is used, while to compute the interstellar dust distribution two approaches are considered, namely, the Eulerian and Lagrangian approaches. For solving the continuity equation in the Lagrangian coordinates, the full Lagrangian method or the Osiptsov method is used. As a result, all the peculiarities of the dust distribution are investigated and it is found that they are located on caustics, i.e., the envelopes of interstellar dust trajectories. Besides it, the regular regions of overdensity (without singularities in the number density) are discovered. It is shown that the dust component accumulation regions are located in a small neighborhood of the heliospheric current sheet, at which the magnetic field changes its polarity, and in the tail of the heliosphere. The effectiveness of the Osiptsov method of solving the continuity equation is compared with the widely used Monte Carlo method (Eulerian approach). It is shown that Monte Carlo method requires extremely high resolution of computational grid to reach the level of accuracy comparable with the Osiptsov method.

Effect of varying cycle time interval and aerosol pre-charge on filtration performance of polyester media

Present study embodies filtration characterization of two nonwoven needle-felt polyester filter materials, viz. PTFE coated and without coated media. The materials have been assessed using flyash aerosol under varying time intervals (6, 9 and 12 min) at different inlet dust densities (50, 90 and 150 g/m3). The flyash particles are charged prior to their deposition over the filter media using a three phase parallel plate box pre-charger at two different levels of pre-charge, viz. 4 kV and 8 kV along with 0 kV. Results reveal that the filtration performance for PTFE coated material is better under all conditions. However, an enhanced filtration performance in terms of particle emission and pressure drop is noted at increased pre-charge level and higher cyclic interval. It may also be noted that the level of improvement in filtration behavior for both the materials has been better at initial level of pre-charge from 0 kV to 4 kV. However, the cumulative behavior of all the factors is also found significant.

The Power of the Rings: The GRB 221009A Soft X-Ray Emission from Its Dust-scattering Halo

GRB 221009A is the brightest gamma-ray burst (GRB) ever detected that has occurred at low Galactic latitude. Owing to this exceptional combination, its prompt X-ray emission could be detected for weeks in the form of expanding X-ray rings produced by scattering in Galactic dust clouds. We report on the analysis of 20 rings, generated by dust at distances ranging from 0.3 to 18.6 kpc, detected during two X‐ray Multi Mirror (XMM)-Newton observations performed about 2 and 5 days after the GRB. By fitting the spectra of the rings with different models for the dust composition and grain size distribution, we reconstructed the spectrum of the GRB prompt emission in the 0.7–4 keV energy range as an absorbed power law with photon index Γ = 1–1.4 and absorption in the host galaxy N H,z = (4.1–5.3) × 1021 cm−2. Taking into account the systematic uncertainties regarding the column density of dust contained in the clouds producing the rings, the 0.5–5 keV fluence of GRB 221009A can be constrained between 10−3 and 7 × 10−3 erg cm−2. Both the fluence and the photon index indicate the presence of a possible soft excess with respect to the extrapolation of the main GRB peak observed at higher energies.

Comparison of the Eulerian and Lagrangian Approaches to Studying the Peculiarities of the Interstellar Dust Distribution in the Heliosphere in the Framework of the Cold Gas Model

Interstellar dust grains penetrate into the heliosphere (region in which the solar wind propagates) due to the relative motion of the Sun and the Local Interstellar Medium (LISM). Inside the heliosphere, the motion of dust particles is mainly governed by the electromagnetic force determined by the heliospheric magnetic field. Under the action of this force, the trajectories of dust grains experience intersections with each other and self-intersections. As a result, dust density accumulation regions appear. These regions are of a great interest in the context of theoretical studying and planning of upcoming space missions. The main aim of the present study is to model the interstellar dust distribution in the heliosphere and investigate the peculiarities of the number density distribution. To describe the dusty component, the cold gas model is used, while to compute the interstellar dust distribution two approaches are considered, namely, the Eulerian and Lagrangian approaches. For solving the continuity equation in the Lagrangian coordinates, the full Lagrangian method or the Osiptsov method is used. As a result, all the peculiarities of the dust distribution are investigated and it is found that they are located on caustics, i.e., the envelopes of interstellar dust trajectories. Besides it, the regular regions of overdensity (without singularities in the number density) are discovered. It is shown that the dust component accumulation regions are located in a small neighborhood of the heliospheric current sheet, at which the magnetic field changes its polarity, and in the tail of the heliosphere. The effectiveness of the Osiptsov method of solving the continuity equation is compared with the widely used Monte Carlo method (Eulerian approach). It is shown that Monte Carlo method requires extremely high resolution of computational grid to reach the level of accuracy comparable with the Osiptsov method.