Deposition Profile Research Articles

Biopharmaceutical Assessment of Mesh Aerosolised Plasminogen, a Step towards ARDS Treatment.

Acute respiratory distress syndrome (ARDS) is a severe complication of lung injuries, commonly associated with bacterial, fungal and viral infections, including SARS-CoV-2 viral infections. ARDS is strongly correlated with patient mortality and its clinical management is very complex, with no effective treatment presently available. ARDS involves severe respiratory failure, fibrin deposition in both airways and lung parenchyma, with the development of an obstructing hyaline membrane drastically limiting gas exchange. Moreover, hypercoagulation is related to deep lung inflammation, and a pharmacological action toward both aspects is expected to be beneficial. Plasminogen (PLG) is a main component of the fibrinolytic system playing key roles in various inflammation regulatory processes. The inhalation of PLG has been proposed in the form of the off-label administration of an eyedrop solution, namely, a plasminogen-based orphan medicinal product (PLG-OMP), by means of jet nebulisation. Being a protein, PLG is susceptible to partial inactivation under jet nebulisation. The aim of the present work is to demonstrate the efficacy of the mesh nebulisation of PLG-OMP in an in vitro simulation of clinical off-label administration, considering both the enzymatic and immunomodulating activities of PLG. Biopharmaceutical aspects are also investigated to corroborate the feasibility of PLG-OMP administration by inhalation. The nebulisation of the solution was performed using an Aerogen® SoloTM vibrating-mesh nebuliser. Aerosolised PLG showed an optimal in vitro deposition profile, with 90% of the active ingredient impacting the lower portions of a glass impinger. The nebulised PLG remained in its monomeric form, with no alteration of glycoform composition and 94% of enzymatic activity maintenance. Activity loss was observed only when PLG-OMP nebulisation was performed under simulated clinical oxygen administration. In vitro investigations evidenced good penetration of aerosolised PLG through artificial airway mucus, as well as poor permeation across an Air-Liquid Interface model of pulmonary epithelium. The results suggest a good safety profile of inhalable PLG, excluding high systemic absorption but with good mucus diffusion. Most importantly, the aerosolised PLG was capable of reversing the effects of an LPS-activated macrophage RAW 264.7 cell line, demonstrating the immunomodulating activity of PLG in an already induced inflammatory state. All physical, biochemical and biopharmaceutical assessments of mesh aerosolised PLG-OMP provided evidence for its potential off-label administration as a treatment for ARDS patients.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Lattice Boltzmann modelling of colloidal suspensions drying in porous media accounting for local nanoparticle effects

A two-dimensional (2-D) double-distribution lattice Boltzmann method (LBM) is implemented to study isothermal drying of a colloidal suspension considering local nanoparticle effects. The two LBMs solve isothermal two-phase flow and nanoparticle transport, respectively. The three local nanoparticle effects on the fluid dynamics considered in this paper are viscosity increase, surface tension drop and local drying rate reduction. The proposed model is first validated by the study of the drying of a 2-D suspended colloidal droplet for two different Péclet numbers, where the evolution of the diameter squared agrees well with experimental results. The model is further validated looking at drying of a colloid in a 2-D capillary tube with two open ends. Compared with experimental results, the best agreement in terms of deposition profile and drying time is obtained when considering all three nanoparticle effects. Afterwards, we apply the model to investigate the complicated drying of a colloidal suspension in a 2-D porous asphalt, considering all three local nanoparticle effects. The drying dynamics, resultant nanoparticle transport, accumulation and deposition are first analysed for a base case. Then a parametric study is conducted varying the initial nanoparticle concentration, porous medium contact angle, nanoparticle contact angle and nanoparticle diffusion coefficient. The influence of these parameters on drying dynamics, drying rate, deposition process and final deposition configurations is analysed in detail, together with the mutual influence of local nanoparticle behaviour. Finally, a unified relation between the average drying rate and the studied parameters is proposed and verified, covering the full parameter ranges of simulations.

Second-harmonic electron-cyclotron resonance heating: A possible impact from mode coupling near the resonance.

The short-wavelength paraxial asymptotic technique, known as Gaussian beam tracing, is extended to the case of two linearly coupled modes in plasmas with resonant dissipation. The system of amplitude evolution equations is obtained. Apart from purely academic interest, this is exactly what happens near the second-harmonic electron-cyclotron resonance if the microwave beam propagates almost perpendicularly to the magnetic field. Because of non-Hermitian mode coupling, the strongly absorbed extraordinary mode may partly transform into the weakly absorbed ordinary mode near the resonant absorption layer. If this effect is significant, it could impair the well-localized power deposition profile. The analysis of parameter dependencies gives insight into what physical factors affect the power exchange between the coupled modes. The calculations show a rather small impact of non-Hermitian mode coupling on the overall heating quality in toroidal magnetic confinement devices at electron temperatures above 200 eV.

Analysis of the local growth and density evolution of soot deposits generated under hydrocarbon condensation: 3D simulation and detailed experimental validation

The utilization of the Exhaust Gas Recirculation (EGR) system during atypical engine operating conditions in order to meet future type-approval criteria exposes the internal surfaces of the devices to exhaust gas with elevated concentrations of particulate matter and greater amounts of hydrocarbon species, leading to the formation of dense and wet sludge deposits. To broaden the understanding of this phenomenon and contribute to the development of advanced EGR devices, this study presents an extended Computational Fluid Dynamics (CFD) model that, in addition to simulating the growth of fouling deposits caused by the accumulation of soot particles, also takes into account the condensation of hydrocarbons. Two scenarios with varying hydrocarbon concentrations in the exhaust flow are analysed, and the evolution of the deposit's thickness and density is determined. A sequential validation process is carried out by comparing the numerical results to actual deposit profiles at different stages of the fouling process. Additionally, hyperspectral images of the fouling layer have been acquired and analysed to validate the regions where hydrocarbon condensation is predicted to play a crucial role, enabling the verification of the hydrocarbon condensation phenomenon predicted by the numerical model. The results obtained under the studied conditions indicate that, on average, 77.4% of the analysed area exhibits a low level of relative error, demonstrating that the proposed model and the methodology used serve as a valuable tool for examining the propensity for deposit formation in devices subjected to fouling exacerbated by hydrocarbon condensation.

60 Multimodal Imaging and Artificial Intelligence Unveil Hot-Spot Deposition, Bronchial/Alveolar Dose and Cellular Fate of Biopersistent Nanoparticles in the Lung

Abstract Pulmonary delivery is not only of increasing importance to exploit local therapy for lung diseases like COVID-19, but also plays an essential role in interpreting health impact of inhaled hazardous (nano-)materials. Deciphering of biodistribution, biokinetics, and cell-mediated immunity of pulmonary delivered nanoparticles (NPs) remains insufficient. We applied state-of-the-art multimodal imaging and deep learning pipelines to elucidate the intricate deposition profiles and the fate of biopersistent NPs in the lung within cellular resolution. Spatially resolved delivery characteristics like inter- and intra-acinar distribution pattern and regional NP dosage were revealed by tissue-clearing light-sheet fluorescence microscopy for six common routes of pulmonary delivery, i.e., intranasal & oropharyngeal aspiration, intubated instillation, microsprayer application, ventilator-assisted & nose-only aerosol inhalation. Artificial intelligence-driven entire airway 3D segmentation (convolutional neural network) enabled accurate dosimetry of bronchial versus acinar/alveolar NP dose (B/A: 0.04 to 0.18 depending on delivery route) rather than the conventionally simplified 2D central-to-peripheral ratio (C/P: 1.32 to 3.79). Moreover, longitudinal 3D imaging revealed similar intra-acinar NP kinetics independent of delivery route. Inhaled NP relocation from the alveolar-epithelium to interstitium was traditionally claimed as the consequence of passive diffusion/transportation of NPs. This study, however, revealed that acinar NP transport can be attributed to the phagocytosis and migration of tissue-resident macrophages (TRMs) as evidenced by complementary analytical approaches (intravital microscopy, ex vivo 4D live-tissue microscopy, in situ immunofluorescence, ex vivo NP-lung interaction model, flow cytometry). Overall, this study elucidates holistic NP-lung delivery and biokinetics features and TRM immunity on the fate of biopersistent NPs.

Real-time control applications of JET heterodyne radiometer electron temperature profiles using ICRH

The Real Time ECE data processing has been recently implemented at JET, by using a cross calibration between the Martin-Puplett interferometer (also known as Michelson) measurements and the Heterodyne faster data. The applicability of RT control with ICRH has been discussed in recent works. In particular, in case of a hollow electron temperature profile, central ICRF heating could be applied to restore temperature peaking. In this work a study about the possibility of controlling the electron temperature profile by using ICRHas an actuator, with inputs from ECE measurements, is described. The ICRH is here used for the optimization of the plasma ramp-down, in order to correct the end of the discharge and avoid the plasma disruption, though a similar approach could also be proposed to improve the plasma performances during the flat top. Preliminary results have been obtained on the physical and logical feasibility of using ICRH in a real-time control loop. A database of good pulses in identifiable conditions has been compiled and validated by covering the main experiments both in the baseline and hybrid scenarios. Such scenarios have been simulated, for a selected numbers of discharges, using the full-wave propagation solver TORIC-SSQLFP, in order to establish the ICRH power deposition profiles to be used to locally restore a peaked electron temperature profile.

A control volume finite-element model for predicting the morphology of cohesive-frictional debris flow deposits

Abstract. To predict the morphology of debris flow deposits, a control volume finite-element model (CVFEM) is proposed, balancing material fluxes over irregular control volumes. Locally, the magnitude of these fluxes is taken proportional to the difference between the surface slope and a critical slope, dependent on the thickness of the flow layer. For the critical slope, a Mohr–Coulomb (cohesive-frictional) constitutive relation is assumed, combining a yield stress with a friction angle. To verify the proposed framework, the CVFEM numerical algorithm is first applied to idealized geometries, for which analytical solutions are available. The Mohr–Coulomb constitutive relation is then checked against debris flow deposit profiles measured in the field. Finally, CVFEM simulations are compared with laboratory experiments for various complex geometries, including canyon–plain and canyon–valley transitions. The results demonstrate the capability of the proposed model and clarify the influence of friction angle and yield stress on deposit morphology. Features shared by the field, laboratory, and simulation results include the formation of steep snouts along lobe margins.

Deposition behaviour of inclined momentum sediment-laden jet

As wastewater is commonly disposed of in the form of sediment-laden jet from a submarine outfall, the sediment movement when the jet evolves in the ambient water and its final deposition are of great importance to marine engineers. This study aims to investigate the settling mechanism of the sediment from an inclined discharge nozzle and quantify the deposition profile for various jet conditions in the hydrostatic environment through physical experiments and dimensional analysis. In the experimental tests, separate flow visualizations for the fluid and sediment phases are achieved to enable the simultaneous observation of sediment particles and jet fluid movement, through which the analysis of the relationship between the fluid and the sediment movement is carried out. The results show that at locations close to the nozzle (s/D = 5), sediment mean velocity has an inverse relationship with the turbulence intensity while positively correlated with the initial jet momentum. The discharge angle is found to have dominant effect on alternating the sediment velocity profile from symmetrical to asymmetrical. With the newly defined momentum settling length scale lmi, the non-dimensional formulations for deposition rate and accumulated deposition profile involving the nozzle inclination have been validated by the experimental data and are potential to be applied to the prediction of depositional rate and final deposition distribution near the outfall for the full-scale wastewater discharge events.

A Comparative Study on the Carcass and Meat Chemical Composition, and Lipid-Metabolism-Related Gene Expression in Korean Hanwoo and Brindle Chikso Cattle.

The objective of this study was to elucidate the effect of cattle breed on carcass and meat chemical composition, fatty acid profiles, and lipid-metabolism-related genes. For this study, same-age Hanwoo and Chikso steers (n = 6 per breed) reared under identical conditions were used. Immediately after slaughter, muscle tissues were collected for analysis of mRNA expression. At 24 h post-mortem, the carcasses were assessed for carcass traits (marbling score, meat yield, etc.), and meat quality and fatty acid profiles in the longissimus lumborum (LL) and semimembranosus (SM) muscles. The results showed that no differences in the slaughter weight, dressing rate, back-fat thickness, trimmed fat, and total meat yield occurred between the two breeds (p > 0.05). However, Hanwoo cattle had a higher marbling score, intramuscular fat (IMF) content, and expression level of lipid-metabolism-related genes such as lipoprotein lipase, peroxisome proliferator-activated receptor gamma, and fatty acid binding protein 4, compared with Chikso (p < 0.05). Contrastingly, Chikso had a higher total unsaturated fatty acid content and expression level of stearoyl CoA desaturase 1 (p < 0.05). It may be said that the difference in the expression levels of lipid-metabolism-related genes could be the molecular factors underlying IMF deposition and fatty acid profile differences in the beef from the two breeds.

ONSHORE-OFFSHORE TRENDS IN THE TEMPORAL RESOLUTION OF MOLLUSCAN DEATH ASSEMBLAGES: HOW AGE-FREQUENCY DISTRIBUTIONS REVEAL QUATERNARY SEA-LEVEL HISTORY

Abstract Surficial shell accumulations from shallow marine settings are typically averaged over centennial-to-millennial time scales and dominated by specimens that died in the most recent centuries, resulting in strongly right-skewed age-frequency distributions (AFDs). However, AFDs from modern offshore settings (outer shelf and uppermost continental slope) still need to be explored. Using individually dated shells (14C-calibrated amino acid racemization), we compared AFDs along an onshore-offshore gradient across the southern Brazilian shelf, with sites ranging from the inner shelf, shallow-water (&amp;lt; 40 m) to offshore, deep-water (&amp;gt; 100 m) settings. The duration of time averaging is slightly higher in deeper water environments, and the AFD shapes change along the depositional profile. The inner shelf AFDs are strongly right-skewed due to the dominance of shells from the most recent millennia (median age range: 0–3 ka). In contrast, on the outer shelf and the uppermost continental slope, AFDs are symmetrical to left-skewed and dominated by specimens that died following the Last Glacial Maximum (median age range: 15–18 ka). The onshore-offshore changes in the observed properties of AFDs—increased median age and decreased skewness, but only slightly increased temporal mixing—likely reflect changes in sea level and concurrent water depth-related changes in biological productivity. These results suggest that on a passive continental margin subject to post-glacial sea-level changes, the magnitude of time-averaging of shell assemblages is less variable along the depositional profile than shell assemblage ages and the shapes of AFDs.

The 3D Structural Architecture of the Human Hand Area Is Nontopographic.

The functional topography of the human primary somatosensory cortex hand area is a widely studied model system to understand sensory organization and plasticity. It is so far unclear whether the underlying 3D structural architecture also shows a topographic organization. We used 7 Tesla (7T) magnetic resonance imaging (MRI) data to quantify layer-specific myelin, iron, and mineralization in relation to population receptive field maps of individual finger representations in Brodman area 3b (BA 3b) of human S1 in female and male younger adults. This 3D description allowed us to identify a characteristic profile of layer-specific myelin and iron deposition in the BA 3b hand area, but revealed an absence of structural differences, an absence of low-myelin borders, and high similarity of 3D microstructure profiles between individual fingers. However, structural differences and borders were detected between the hand and face areas. We conclude that the 3D structural architecture of the human hand area is nontopographic, unlike in some monkey species, which suggests a high degree of flexibility for functional finger organization and a new perspective on human topographic plasticity.SIGNIFICANCE STATEMENT Using ultra-high-field MRI, we provide the first comprehensive in vivo description of the 3D structural architecture of the human BA 3b hand area in relation to functional population receptive field maps. High similarity of precise finger-specific 3D profiles, together with an absence of structural differences and an absence of low-myelin borders between individual fingers, reveals the 3D structural architecture of the human hand area to be nontopographic. This suggests reduced structural limitations to cortical plasticity and reorganization and allows for shared representational features across fingers.

Modeling the Transition between Localized and Extended Deposition in Flow Networks through Packings of Glass Beads

We use a theoretical model to explore how fluid dynamics, in particular, the pressure gradient and wall shear stress in a channel, affect the deposition of particles flowing in a microfluidic network. Experiments on transport of colloidal particles in pressure-driven systems of packed beads have shown that at lower pressure drop, particles deposit locally at the inlet, while at higher pressure drop, they deposit uniformly along the direction of flow. We develop a mathematical model and use agent-based simulations to capture these essential qualitative features observed in experiments. We explore the deposition profile over a two-dimensional phase diagram defined in terms of the pressure and shear stress threshold, and show that two distinct phases exist. We explain this apparent phase transition by drawing an analogy to simple one-dimensional mass-aggregation models in which the phase transition is calculated analytically.

Prediction of deposit characteristics based on the discrete coaxial nozzle during laser direct metal deposition

The variation in powder mass concentration distribution caused by the nozzle structure influence the deposit profiles and quality to a considerable extent in laser direct metal deposition (DMD) process. For symmetrical discrete nozzles, the powder mass concentration distribution was described, and the results were utilized in a molten pool model without powder feeding simulations. The evolution of the molten pool dimensions, and the temperature and velocity fields of single-track deposit were explored. The influences of specific energy (E) and mass per unit length (MUL) on the characteristics of single-track deposits were investigated. The correlation between the powder stream position and the concentration distribution was clearly expressed. The results indicated that the width/height ratio of single-track deposits decreased significantly, and the contact angle first increased and then decreased with higher specific energy intensity. Besides, the variation in the spatial position of the powder stream led to different mass concentration distributions, resulting in the tilt of deposit cross-sections towards the side with a higher mass concentration. The model exhibited a capacity for predicting the profiles of the deposits formed by symmetrical discrete nozzles.

Dose voxel resolution determination for Monte Carlo electron beam simulation in thin targets.

Monte Carlo particle simulation has become the primary tool for designing low-energy miniature x-ray tubes due to the difficulties of physically prototyping these devices and characterizing their radiation fields. Accurate simulation of electronic interactions within their targets is necessary for modelling both photon production and heat transfer. Voxel-averaging can conceal hot spots in the target heat deposition profile that can threaten the integrity of the tube. This research seeks a computationally-efficient method of estimating voxel-averaging error in energy deposition simulations of electron beams penetrating thin targets to inform the appropriate scoring resolution for a desired accuracy level. An analytical model to estimate voxel-averaging along the target depth was developed and compared to results from Geant4 via its wrapper, TOPAS. A 200 keV planar electron beam was simulated to impinge tungsten targets of thicknesses between 1.5- and 12.5- . For each target, the model was used to calculate the energy deposition ratio between voxels of varying sizes centered on the longitudinal midpoint of the target. Model-calculated ratios were compared to simulation outputs to gauge the model's accuracy. Then, the model was used to approximate the error between the point value of electron energy deposition and a voxel-based measurement. The model underestimates error to within 5% for targets less than 7.5- in thickness with increasing error for greater thicknesses. For the 1.5- target, calculations of the point-vs.-voxel energy deposition show an 11% averaging effect between the midpoint and a 1.5- voxel. Energy deposition profiles along the target depth were also calculated in the Monte Carlo for reference. A simple analytical model was developed with reasonable accuracy to guide Monte Carlo users in estimating the appropriate depth-voxel size for thin-target x-ray tube simulations. This methodology can be adapted for other radiological contexts to increase robustness in point-value estimations. This article is protected by copyright. All rights reserved.

Influence of Nozzle Type and Wind Speed on Deposition and Interception of Pesticide Spray Drift: A Case Study with Atrazine

A wind tunnel study was conducted to compare spray drift deposition and interception profiles across ASABE (American Society of Agricultural and Biological Engineers) coarse, very coarse, and extremely coarse drop size distribution (DSD) categories as a function of wind speed. AAtrex 4L (atrazine) was used as the spray solution; disk (deposition) and rod (interception) sampling devices were deployed at multiple distances and subject to spray drift at multiple wind speeds. Drift deposition was equivalent for the coarse spray delivered at 10 mph [16.1 km/h] and the extremely coarse spray delivered at 15 mph [24.1 km/h]. Intercepted (airborne) drift was indistinguishable between the coarse spray delivered at 10 mph [6.2 km/h] and very coarse spray delivered at 15 mph [6.2 km/h], and very coarse spray delivered at 10 mph [6.2 km/h] and extremely coarse spray delivered at 15 mph [24.1 km/h]. Regulatory decisions regarding potential buffer/setback mitigations would benefit from leveraging results regarding nozzle and wind speed relationships reported in this study and others to better utilize available experimental drift data (e.g., field studies/bioassays) generated with a single nozzle but at wind speeds exceeding the label specification.

Simulations of hot electron transport in the radiation-ablated plasmas

Abstract The transport of hot electrons in inertial confinement fusion (ICF) is integrated problem due to the coupling of hydrodynamic evolution. Here a hot electron transport code is developed and coupled to the radiation hydrodynamic code MULTI1D. Using the code, the hot electron beam slowing-down and ablation processes are simulated. The ablation pressure scaling law of hot electron beams is confirmed in our simulations. We attempt to simulate the hot electron transport in the condition of indirect drive ICF, where the spatial profile of hot electron energy deposition is presented around the compressed region. It is shown the hot electron can prominently increase the total ablation pressure in the early phase of radiation-ablated plasmas. So, our studies suggest a potential driven asymmetry mechanism may occur due to irradiation of asymmetry energetic hot electron beam. The possible degradation from the hot electron transport and preheating is also discussed.

Wall conditioning effects and boron migration during boron powder injection in ASDEX Upgrade

The efficacy of boron powder injection as a wall conditioning tool method in terms of its ability to create a sufficiently uniform boron layer on plasma-facing surfaces has been studied in ASDEX Upgrade. Boron powder was injected in two series of dedicated plasma discharges at varied injection rates and total amount injected. The resulting boron deposition was determined quantitatively by exposure of witness samples followed by ex-situ surface analysis of the retrieved samples. In both experiments, isotopically enriched boron was used to distinguish the deposition of the newly injected material from the residual boron fraction in the machine originating from previous glow discharge boronisations. It could be confirmed that the injected boron is migrating and re-deposited across plasma-facing wall surfaces already within one discharge. At erosion dominated divertor areas, the boron influx from the main chamber results in formation of a mixed tungsten-boron surface layer with a boron area density of O(1nm) whereas at deposition dominated areas closed boron layers grow with ongoing boron injection to a thickness of up to O(1μm). Extrapolating the radial boron deposition profile on the samples exposed in the main chamber to the limiter front yields a similar boron coverage of O(1μm), which is about ten times higher than typical values for glow discharge boronisation. Together with the observed reduction of oxygen level and improved wall pumping, the surface analysis results demonstrate that boron powder injection provides a suitable means to refresh the wall conditioning effect of a preceding glow discharge boronisation.

Comparison of Pulsed Electroacoustic Measurements and AF-NUMIT3 Modeling of Polymers Irradiated with Monoenergetic Electrons

Successful spacecraft design and charging mitigation techniques require precise and accurate knowledge of charge deposition profiles. This paper compares models of charge deposition and transport using a venerable deep dielectric charging code, AF-NUMIT3, with direct measurements of charge profiles via pulsed electroacoustic (PEA) measurements. Eight different simulations were performed for comparison to PEA experiments of samples irradiated by 50 or 80 keV monoenergetic electrons in vacuum and at room temperature. Two materials, polyether-ether ketone (PEEK) and polytetrafluoroethylene (PTFE), were chosen for their very low conductivities so that minimal charge migration would occur between irradiation and PEA measurements. PEEK was found to have low acoustic attenuation, while PTFE has high acoustic attenuation through the sample thicknesses of 125 and for each material. The measurements were directly compared to AF-NUMIT3 simulations to validate aspects of the code and to investigate the importance of various simulation options, as well as to characterize the PEA instrumentation, measurement methods, and signal processing used. The measurement and simulation values for magnitude of charge deposition, penetration depth, and charge deposition spatial profiles are largely in agreement, though spatial and temporal distributions in incident electron flux and effects of radiation-induced conductivity (RIC) and delayed RIC during the deposition process complicate the process. This work provides an experimental validation of the AF-NUMIT3 deep dielectric charging code and insight into the accuracy and precision of the PEA method.

A CFD-based approach to study the deposition and distribution behaviour of 212Pb in a calibration chamber.

Among the several aspects of decay products behavior, deposition is of special significance because of its prominent role in the activity removal from the environment, which eventually results in the occurrence of decay product disequilibrium with the parent gas. This point is particularly important in case of thoron dosimetry where thoron progeny 212Pb accounts for the most of the radiological dose. The deposition depends on the size distribution of decay products and the structure of air turbulence at the air-surface interface. In the present work, the effect of varying air-flow (fan speed) and aerosol count median diameter (CMD) was studied on the deposition and distribution profile of 212Pb using computational fluid dynamics (CFD). The simulations have been carried out in a cubical calibration chamber of volume 8 m3, facilitated at RP&AD, BARC. Simulated results showed that the increase of total depositional loss rate of attached fraction of 212Pb due to increase of the fan speed was significant for CMD up to 400nm, beyond which this effect started becoming less prominent with increasing diameter. Besides, a minimum of the total depositional loss rate curve was seen to be shifted to the higher CMD with increase of the fan speed. CFD results were found to be in good agreement with experimental observations obtained in the controlled conditions with thoron source.