Particle Deposition Research Articles

A finite volume approach to dosimetric calculations in diffusing alpha-emitters radiation therapy

Objective.In diffusing alpha-emitters radiation therapy ('Alpha DaRT'), the diffusion-leakage (DL) model is used to determine the spatial distributions of the emitters and the corresponding alpha dose, critical for a successful treatment. This work first introduces a finite volume (FV) approach to develop numerical schemes to simulate the DL model in one, two and three dimensions then presents how variations over realistic ranges of the DL model parameters related to desorption, diffusion and leakage processes affect the alpha dose distribution and the position of the clinically significant alpha particle10Gy isodose. This work also presents the effects of three modeling approximations: two source geometry approximations (solid cylinder instead of hollow, pixelized cross section instead of circular), and one dosimetric approximation (single-source dose superposition instead of multiple-sources direct dose calculation).Approach.The introduced FV approach was used to obtain spatial distributions of the emitters, from which the corresponding alpha dose distributions were calculated under the assumption of a local deposition of the alpha particles' energies. Variation ranges of the DL model parameters were based on previously published data. For each modeling approximation studied, the error and relative error on the alpha dose distribution were calculated and the displacement of the10Gy isodose was evaluated.Main results.Over realistic ranges, the desorption probabilities, diffusion lengths, and leakage probabilities affect the position of the alpha particle10Gy isodose by∼0.1mm,∼1.5mm and∼0.5mm, respectively. The three modeling approximations studied have a negligible effect on the alpha particle10Gy isodose position, with displacements⩽0.01mm.Significance.This work quantitatively evaluates the relative importance of different parameters and approximations in Alpha-DaRT alpha dose calculations based on their impact not only on the dose variation at a given distance from the source but also on the displacement of clinically significant isodoses.

Numerical Evaluation of Aerosol Propagation in Wind Instruments Using Computational Fluid Dynamics

This paper examines aerosol propagation in wind instruments through numerical analysis, focusing on particle trajectories within five types of wind instruments: saxophone, clarinet, flute, oboe, and trumpet. Using a computational fluid dynamics approach, it is found that larger particles are deposited within the instruments, while smaller micron-sized particles predominantly exit through the bell. The impact of the instrument’s geometry on aerosol dynamics is quantified; cylindrical instruments (clarinet, flute) show an increased rate of small droplet deposition or escape through tone holes compared to conical instruments (saxophone, oboe). Instruments with steep turnings, such as the trumpet, exhibited significant particle deposition. The study suggests that deposited particles are likely to move towards re-emission points, driven by gravity and airflow, especially in straight-shaped instruments. Integrating computational fluid dynamics (CFD) as a complementary approach to traditional experimental methods provides insights into aerosol transmission mechanisms in musical settings. This methodology not only aids in understanding aerosol behavior but also supports the development of safer musical and educational environments, contributing to the field.

Surface-Enhanced Raman Scattering on Size-Classified Silver Nanoparticles Generated by Laser Ablation.

This study delved into the complex interplay between the nanostructural characteristics of nanoparticles and their efficacy in surface-enhanced Raman scattering (SERS) for sensitive detection of trace chemical substances. Silver nanoparticles were prepared for the SERS substrate by combining laser ablation, postannealing processes (up to 500 °C), and electrostatic mobility classification, allowing high-purity silver nanoparticles with controlling their sizes (40-100 nm) and aggregate structures. These nanoparticles were then inertially deposited on the substrates to create SERS-active surfaces, employing Rhodamine B as a probe to assess the impact of particle size, shape, and deposition density on SERS effectiveness. Our findings revealed that spherical nanoparticles, especially those approximately 50 nm in diameter, controlled to a spherical structure through gas-phase annealing at 500 °C and subsequent classification, yielded the most significant SERS enhancement. This optimal can be explained by the particle size response of the surface plasmon resonance, where the enhancement of the Raman signal for particles up to 50 nm (1/10 of the laser wavelength used in this study, 532 nm) arises from a balance between the enhancement of dipole moment and the number of "hot spot" regions (respectively proportional to the cube and inverse square of the diameters in theory, leading to a linear relationship between signal intensity and particle diameter); meanwhile, in larger size region than 50 nm, the Raman signal was decreased owing to the attribution of the phase difference between the electric field and dipole moment. Furthermore, we found that a deposition density of 2 μg resulted in nearly a single layer of particles, which is crucial for maximizing SERS hotspots and, consequently, the enhancement effect.

Evaluating the role of sex-related structure-function differences on airway aerosol transport and deposition.

Several experimental studies have found that females have higher deposition of particles in the airways compared with males. This has implications for the delivery of aerosolized therapeutics and for understanding sex differences in respiratory system response to environmental exposures. This study evaluates several factors that potentially contribute to sex differences in particle deposition, using scale-specific structure-function models of 1D ventilation distribution, particle transport, and deposition. The impact of gravity, inhalation flow rate, and dead space are evaluated in 12 structure-based models (seven female; five male). Females were found to have significantly higher total, bronchial, and alveolar deposition than males across a particle size range from 0.01 to 10 . Results suggest that higher deposition fraction in females is due to higher alveolar deposition for smaller particle sizes, and higher bronchial deposition for larger particles. Females had higher alveolar deposition in the lower lobes, and slightly lower particle concentration in the left upper lobe. Males were found to be more sensitive to changes due to gravity, showing greater reduction in bronchial deposition fraction. Males were also more sensitive to change in inhalation flow rate, and to scaling of dead space due to the larger male baseline airway size. Predictions of sex differences in particle deposition - that are consistent with the literature - suggest that sex-based characteristics of lung and airway size interacting with particle size gives rise to differences in regional deposition.

Isotopic characteristics of extreme “dragon-boat water” rainfall between mid-May and mid-June in 2022 in Fuzhou, southeastern China

With global warming, the surge in torrential “dragon-boat water” (DBW) events during mid-May and mid-June, following the onset of the South China Sea summer monsoon (SCSSM), poses escalating threats to southern China through severe flooding and impacts on human livelihoods and socio-economic development. To better understand their fundamental mechanisms, we investigated extreme DBW rain events that occurred in southeastern China in 2022. Analysis of stable isotopes in precipitation samples collected in Fuzhou before and after SCSSM onset uncovered a significant decrease in δ18O values following monsoon onset, indicating intensified regional convective activity. This decrease is attributed to the seasonal variation in moisture sources, with water vapor originating from distant oceans after SCSSM onset contributing to increased Rayleigh distillation and subsequent δ18O reduction. A negative correlation between upstream rainfall and δ18O values, particularly at 96 h along the backward trajectory, indicates the influences of accumulative convective activities on precipitation isotopes along water vapor transport paths. Individual rain events typically exhibit characteristic “V” or “W” shapes in δ18O, with the lowest values mostly observed in stratiform zone, governed by microphysical processes, such as mesoscale subsidence, vapor deposition of ice particles, and rain re-evaporation below cloud-base. Notably, events with low δ18O values often coincide with low initial values, suggesting decreased vapor δ18O before precipitation due to accumulative convection or upstream rainout. Our findings elucidate the mechanisms driving the long-term changes in precipitation isotopes and their evolution during DBW events, enriching our understanding of the interplay between precipitation isotopes, large-scale convection, and microphysical processes.

Modeling the clogging process of leachate collection systems in municipal solid waste landfills: The role of temperature

The leachate collection system (LCS) is an important component of barrier systems in municipal solid waste (MSW) landfills. LCS Failure due to clogging could lead to leachate accumulation, potential soil and groundwater pollution and slope failure. LCS clogging is generally ascribed to particle deposition, biofilm growth, and calcium carbonate precipitation, while temperature strongly influences microbial activity and thus inevitably affects the clogging process of LCSs. However, the role of temperature in the process of clogging and leachate accumulation in LCSs remains unclear. The main objective of this study was to bridge this research gap by developing reasonable mathematical models and comprehensively analyzing this issue. The mathematical model involved leachate flow, solute migration, physical–chemical-biological clogging, and heat transfer processes. By conducting a series of numerical simulations, the temperature variation, clogging development, and corresponding leachate accumulation inside the system during long-term operation in both the geotextile and gravel layers were numerically analyzed and predicted. The results demonstrated that, in the gravel layer, due to the higher temperature, more thorough microbial substrate consumption led to higher production of carbonate ions and hence faster and more notable calcium carbonate precipitation. Overall, the bioactivity changes due to high temperatures could considerably accelerate the failure of LCS.

Study on Flow Heat Transfer and Particle Deposition Characteristics in a Kettle Reboiler

Study on Flow Heat Transfer and Particle Deposition Characteristics in a Kettle Reboiler

Field-Assisted Efficient Capturing and Analysis of Airborne Nanoparticulate Matter Using a Multifunctional Nanoporous Membrane.

As the potential adverse health and environmental effects of nanoscale pollutants have garnered significant attention, the demand for monitoring and capturing ultrafine particulate matter has been growing. With the rise in ultrafine dust emissions, this issue has become increasingly important. However, submicron particles require advanced strategies to be captured because of their limited inertial effect. For example, electrostatic air filters have been investigated for their improved performance in the fine particle regime. On the other hand, Raman spectroscopy was proposed as a promising analytical strategy for aerosol particles because it can be used to conveniently detect analytes in a label-free manner. Thus, the synergistic integration of these strategies can open new applications for addressing environment-related challenges. This study presents a multifunctional approach for achieving both air filtration and surface-enhanced Raman scattering (SERS) for analyte identification. We propose a nanoporous membrane composed of a thin gold layer, copper, and copper oxide to provide the desired functions. The structures are produced by performing scalable electrodeposition and subsequent electron-beam evaporation, attaining an excellent filtration efficiency of 95.9% with an applied voltage of 5 kV for 300 nm KCl particles and a pressure drop of 121 Pa. Raman intensity measurements confirm that the nanodendritic surface of the membrane intensifies the Raman signals and allows for the detection of 10 μL of nanoplastic particle dispersion with a concentration of 50 μg/mL. Rhodamine 6G aerosol stream with an approximate particle deposition rate of 0.040 × 106 mm-2·min-1 is also identified in a minimum detectable time of 50 s. The membrane is shown to be recyclable owing to its structural robustness in organic solvents. In addition, the fatigue resistance of the structure is evaluated through 22,000 iterative loading cycles at a pressure of 177 kPa. No performance degradation is observed after the fatigue loading.

A numerical investigation on the dynamics of particle deposition and fouling on a vertical falling film pipe

The zero liquid discharge process is designed to eliminate the discharge of industrial wastewater into the environment, addressing significant environmental concerns that have emerged in recent decades. Falling film evaporator is one of the primary technologies employed in these systems. As observed, there is a noticeable lack of research numerically simulating these phenomena in a vertical pipe including falling film flow. In the present study, an effort has been made to address the existing research gap by conducting numerical simulation of particles deposition and fouling phenomena in a falling film flow in a three-dimensional vertical pipe using computational fluid dynamics. Continuous phases which contain two non-penetrating fluids, i.e., air and water, are simulated using volume of fluid multiphase model and the large eddy simulation turbulence model. Meanwhile, particles motion has been tracked utilizing discrete phase model. Water film enters the pipe with a thickness of 3.7 mm and an inlet velocity of 1 m/s, and particles with a density of 3110 kg/m3 are injected through the water inlet surface in various cases, each with different diameters. As observed, with an increase in particles diameter from 5 to 15 μm, the asymptotic total fouling mass has increased over 14 times, reaching from 0.016 to 0.18 kg/m2, and the total number of deposited particles has also increased. By increasing the fluids inlet velocity from 1 to 1.5 m/s, the total number of deposited particles has decreased throughout the pipe wall, and the total fouling mass has experienced a reduction of 55.8 %.

Influence of aloe-vera powder addition on microstructure and mechanical properties of wire + arc additively manufactured ER70S-6 steel

ER70S-6 steel Wire Arc Additive Manufactured deposit was fabricated using Gas Tungsten Arc Welding (GTAW) under two conditions: without and with aloe-vera powder. Aloe-vera is added at the interlayer during deposition. The effect on microstructure evolution, hardness and tensile properties due to addition of aloe-vera were investigated. Without aloe-vera deposits recorded non-uniform microstructure from lower to upper zone, resulting in wide variation in hardness. On the other hand, presence of aloe-vera minimized the microstructural inhomogeneities. The presence of aloe-vera also suppressed the formation of bainite phase and stabilize the hardness throughout the deposit. The tensile strength of the aloe-vera added deposit also increases compared to without powder particle deposit.

CFD modeling of spray drying of fresh whey: Influence of inlet air temperature on drying, fluid dynamics, and performance indicators

Whey is a very perishable food and a potent source of protein. It might be more commercialized through the process of spray drying, which would enhance its shelf life. No CFD computational models applied to the drying of fresh sweet whey have been reported in the literature to investigate transport phenomena in spray dryers and to predict crucial design parameters such as deposition, powder recovery, and drying efficiency. Using an Eulerian-Langragean technique, the behavior of multiphase flow as well as heat and mass transfer were investigated. The influence of the inlet air temperature was evaluated in relation to the velocity profiles of the continuous and discrete phases, the residence time distribution, the particle diameter formed, the air temperature near the injection zone, the particle temperature, and the mass fraction of evaporated water. Furthermore, performance parameters such as powder recovery, particle deposition, and drying efficiency were projected for varied air inlet temperatures. The velocity, residence time, and particle size distribution patterns were similar for the different air inlet temperatures. Greater variations might be noticed in the injection zone, especially in the temperature and mass fraction profiles. The lowest drying temperature resulted in the lowest particle deposition and the best thermal efficiency, making it the optimal process condition. This investigation can serve as a benchmark for the design of optimized spray dryers with greater thermal efficiency and yield to produce powdered whey.

Effects of manganese and copper ions on fouling formation in agricultural irrigation pipelines fed with brackish water

Brackish water utilization has emerged as a promising solution to address water scarcity issues. However, fouling poses significant technical and economic challenges to brackish water distribution systems (BWDS). Manganese (Mn2+) and copper (Cu2+) ions are common in brackish water, yet their impacts on BWDS fouling remain largely unknown. This study investigated the effects of four concentrations of Mn2+ (0.05, 0.5, 1.5, and 3.0 mg L−1) and four concentrations of Cu2+ (0.02, 0.2, 0.6, and 1.2 mg L−1) on fouling dynamics in BWDS. The results indicate that BWDS fouling significantly increased at higher concentrations of Mn2+ and Cu2+. Compared to a concentration of 0.05 mg L−1 of Mn2+, concentrations ranging from 0.5 to 3.0 mg L−1 increased fouling total weight by 29.9 % to 63.0 %. Similarly, compared to a concentration of 0.02 mg L−1 of Cu2+, concentrations ranging from 0.2 to 1.2 mg L−1 increased fouling weight by 16.9 % to 59.1 %. Although Mn2+ and Cu2+ aggravated BWDS fouling, no Mn2+ or Cu2+ chemical precipitations were detected in the fouling components. It is likely that Mn2+ and Cu2+ cations act as a “bridge” between water particles, facilitating flocculation and particle deposition, thereby increasing particulate fouling (e.g., quartz and silicates) in BWDS. Additionally, increased particulate fouling provided more nucleation sites for calcium carbonate precipitation, which significantly raised the content of calcium carbonate fouling. Therefore, it is recommended that the concentrations of Mn2+ and Cu2+ be maintained below 1.5 mg L−1 and 0.6 mg L−1, respectively, to mitigate BWDS fouling. This study elucidates the underlying mechanisms of Mn2+ and Cu2+ influence on BWDS fouling, offering valuable insights for the utilization of brackish water in efforts to mitigate global water scarcity.

On the use of slurry as an alternative to dry powder for laser powder bed fusion of 316L stainless steel

Laser powder bed fusion (LPBF) is a well-established additive manufacturing process for producing high-quality metal components with unparallelled design freedom. However, LPBF also has its limitations, including a limited materials palette, low productivity and high costs, mainly due to the expensive feedstock powders. These powders must meet highly stringent requirements regarding particle size (15–45μm), particle size distribution (mono-modal) and morphology (spherical), which is achievable only through expensive gas- and plasma-atomised powders. This paper investigates slurry-LPBF as an alternative to conventional dry powder LPBF. The use of slurry removes some of the stringent powder requirements by allowing deposition of smaller particles with a variety of particle morphologies. Slurry-LPBF can therefore increase the useful yield of the atomisation process and expand the materials palette for LPBF, by enabling the use of powders for which atomised variants are not commercially available. This study used 316L stainless steel powder with an average particle size <18μm. An existing slurry-LPBF machine was re-designed and re-built, allowing successful slurry processing. Two optimal parameter sets were obtained, resulting in component density of 99.4%. Tensile testing revealed an ultimate tensile strength (UTS) of 622 ± 2 MPa and an elongation at break of 66 ± 2%. These results are consistent, and fall within the range of reported values in literature for dry-powder LPBF, with the UTS being on the lower side of the range, whilst elongation at break being on the higher side.

The role of puff volume in vaping emissions, inhalation risks, and metabolic perturbations: a pilot study

Secondhand vaping exposure is an emerging public health concern that remains understudied. In this study, saliva and exhaled emissions from ENDS users (secondhand) and non-ENDS users (baseline) were collected, firsthand emissions were generated using an automated ENDS aerosol generation system programmed to simulate puffing topography profiles collected from ENDS users. Particulate concentrations and sizes along with volatile organic compounds were characterized. We revealed puffing topography metrics as potential mediators of firsthand and secondhand particle and chemical exposures, as well as metabolic and respiratory health outcomes. Particle deposition modeling revealed that while secondhand emissions displayed smaller deposited mass, total and pulmonary particle deposition fractions were higher than firsthand deposition levels, possibly due to smaller secondhand emission particle diameters. Lastly, untargeted metabolomic profiling of salivary biomarkers of lung injury due to firsthand ENDS exposures revealed potential early indicators of respiratory distress that may also be relevant in bystanders exposed to secondhand vaping scenarios. By leveraging system toxicology, we identified 10 metabolites, including leukotriene D4, that could potentially serve as biomarkers for ENDS use, exposure estimation, and the prediction of vaping-related disease. This study highlights characterization of vaping behavior is an important exposure component in advancing our understanding of potential health effects in ENDS users and bystanders.

Optimal spur dike orientation for scour mitigation under downward seepage conditions

Abstract River bank protection is vital in hydraulic river engineering to preserve natural rivers, lands, and critical constructions such as bridges. Spur dikes are erosion-protective structures that protrude outward from the river bank in different orientations to deflect the flow away from the riverbank. The present experimental study provides insight into the temporal variation in bed morphology and scours around rectangular-shaped spur dikes with different orientations, such as 60º, 90º, and 120º. Also, maximum scour depth (MSD) is developed compared to the condition when downward seepage is applied. The experiments examined the suitability of various spur dike orientation configurations and the scour development over time, specifically at intervals of 2, 12, and 24 hours, and compared with 24 hours (Seepage). Results showed that the orientation angle of 90º generated the highest scour depth, while the least scour depth was found with an orientation angle of 120º. The downward seepage intensifies the motion of sediment particles and leads to an escalated particle detachment, resulting in deeper scour depressions. The development of scour depth is initiated from the spur dike tip and reaches its maximum there. The deposition of sand particles shifted downstream, and a dune-like structure formed near the second spur dike.

Energy-efficient ventilation strategies at hospital front desks for minimizing infectious particle dispersion: Considering patient postures and airflow optimization

This research presents a novel examination of infectious particle dispersion at hospital front desks, analysing the impact of different patient postures on particle dynamics. It evaluates the efficacy of various ventilation strategies in mitigating particle spread within this high-risk area. Specifically, this study innovatively assesses particle dispersion associated with three common patient postures: upright standing, sitting in a wheelchair, and lying on a mobile bed. Results showed the baseline ventilation that considers the upright standing patient has the highest particles (34) adhered on the nurse. Particle adherence decreases with the sitting (29 particles) and lying postures (20 particles), underscoring the significant influence of human posture on particle distribution. The key contribution of this study is the identification of an optimized ventilation strategy which installs low-level wall-mounted air supply diffusers and ceiling-mounted exhaust grilles, as demonstrated in Case 3. This strategy effectively reduces particle deposition on the nurses and visitors by 52.9 % and 40 %, respectively. These findings advocate for practical infection control measures, like barriers between nurses and patients, to better protect healthcare workers. The study also suggests that future research should account for more crowded environments and occupant movement to better reflect real-world conditions at hospital front desks.

Influence of particle parameters on deposition onto healthy and damaged human hair.

This research investigates how particle parameters, such as zeta potential, size, functional group, material composition, and hydrophobicity affect their affinity and deposition of particles onto hair. Streaming potential was used as the technique for analysis. The streaming potential data obtained was then converted to surface coverage data. Scanning electron microscopy (SEM) was also done to visualize particle localization on the hair surface. This study found stronger particle affinity on healthy than on damaged (oxidatively bleached) hair, due to diminished interaction sites from the removal of the hair shaft's external lipid layer. SEM imaging supported these findings and offered insights into particle localization. Hydrophilic silica particles accumulated along the exposed hydrophilic cuticle edges of healthy hair, due to hydrogen bonding with the exposed endocuticle. This localization is hypothesized to be due to the limited hydrophilic binding sites on the hydrophobic healthy hair cuticle surface. In damaged hair, an abundance of hydrophilic sites across the cuticle surface results in more dispersed binding. Hydrogen bonding and electrostatic attraction were shown to be the predominant forces influencing deposition, with hydrophobic interactions playing a less influential role. The affinity studies also proved that electrostatic attractions work over a longer range and are more effective at lower particle conditions compared with hydrogen bonding which only start to play a bigger role at higher particle concentrations. Steric hindrance of bulky side groups acted as a significant repulsive force. Results also revealed that larger particles deposit poorly on both healthy and damaged hair compared with smaller ones. Compared with neutrally charged silica nanoparticles (SN-2), positively charged PMMA particles (PN+16) have a stronger affinity to healthy hair, with highly charged particles (PN+49) depositing most rapidly. This study provides a fundamental understanding of how particle-surface parameters influence their affinity to hair and how damaging hair affects deposition.

Effect of airway wall motion on particle deposition and delivery in the neonatal trachea

Modeling pulmonary drug delivery in the airway using computational fluid dynamics (CFD) simulations tracks drug particles throughout the airway, providing valuable information on the deposition location of inhaled drugs. However, most studies simulate particle transport within static airway models that do not incorporate physiological airway motion; this choice limits accuracy since airway motion directly affects particle transport and deposition, notably in newborns with airway abnormalities such as tracheomalacia. The objective of this study is to determine the effect of airway motion on drug delivery in neonates with and without airway disease. For this study, two control subjects without any airway disease and three subjects with tracheomalacia (dynamic tracheal narrowing) were enrolled. Each subject was imaged at approximately 40-weeks post-menstrual age using magnetic resonance imaging (MRI). MRI data were retrospectively reconstructed to obtain static airway images gated to different time points of the breath (i.e., end expiration and end inspiration) and an image representing combined data from all timepoints (ungated). Virtual airway surfaces (pharynx to main bronchi) were made from each MR image. A moving airway surface was created from surface registration of these surfaces and used as the boundary for a CFD simulation of one inhalation, along with subject-specific inspiratory flow waveforms. To assess the effect of airway wall motion on particle deposition, static-walled simulations, based on the airway surfaces at end inspiration, end expiration, and the ungated airway surface, were also performed using the same flow boundary conditions. Particle transport (particles diameter range 0.5–15 μm) was compared between the simulations during the inhalation. Airway surface motion affected particle transport into the small airways by 65% on average (0.5–5 μm– 22%, 5-15 μm– 86%) compared to static-walled simulations, while comparison between static end expiration and other static-walled simulations using geometries acquired during different phases of breathing differed by more than 500% on average (0.5–5 μm– 45%, 5-15 μm– 741%). For particle deposition, airway surface motion affected by 43% on average (0.5–5 μm– 86%, 5-15 μm– 21%) compared to static-walled simulations and comparison between static end expiration and other static-walled simulations differed by 47% on average (0.5–5 μm– 58%, 5-15 μm– 41%). Differences between dynamic and static deposition results and between static simulations from different timepoints occurred in patients with and without airway disease. This study suggests the importance of using airway wall motion in CFD simulations to model aerosolized drug delivery in the airway. If a CFD simulation is limited to only a static airway image without physiological motion, particle deposition mapping may yield markedly inaccurate results, potentially resulting in higher or lower drug dosing than intended.

Numerical Analysis of Pressure Drop and Photoresist Particle Defect Accretion in HVAC Pipe System with Dampers

The operational efficiency of HVAC (Heating, Ventilation, and Air Conditioning) systems is significantly impacted by the accumulation of particles leading to duct blockages. This research investigates the implementation of Lateral Dampers and Butterfly Dampers for airflow control, delving into the intricate mechanisms governing pressure loss within ducts due to particle deposition.Efficient HVAC operation is paramount for energy conservation and indoor air quality. The hindrance caused by particle deposition-induced blockages in ducts impedes system efficiency. This study innovates airflow control mechanisms critical for optimizing energy consumption and ensuring sustainable HVAC performance.Highlighting the novelty of this study, while prior research has explored fluid dynamics and particle deposition within ducts, the nuanced effects of damper configurations on particle deposition and pressure loss remain largely unexplored. This research addresses this gap by investigating the interplay between damper states, particle deposition, and pressure losses within HVAC duct systems.The primary objective is to unravel the relationship between damper configurations and particle accretion within HVAC ducts. Utilizing Inventor 3D modeling and Computational Fluid Dynamics (CFD) simulations employing DPM (Discrete Phase Model) and Accretion Model, the study provides insights into how damper states influence particle deposition and subsequent pressure losses. The use of the Eulerian Wall Film (EWF) model enhances the accuracy of predicting the accretion on duct and damper surfaces.Furthermore, this study extends its scope to investigate the particle information resulting from the photoresist bake process, including the generation of outgas and the principal component, benzo-pyrene. Specifically, the study examines the industrial duct's particle accretion and film formation arising from the interaction of these particles during outgas transport.Findings reveal that, for Damper 1 to 3, variations in opening ratios have negligible effects on pressure within 5 Pa, suggesting minimal influence on system performance. Notably, Butterfly Dampers demonstrate a unique behavior where any one damper reaching full closure immediately results in a pressure drop to zero. Moreover, Butterfly Damper 1 and 2 significantly impact pressure, showcasing that at a 45-degree opening, the particle deposition rate is approximately 0.5 times the rate of pressure change.The key takeaway is the development of a sophisticated algorithm for damper control, maintaining consistent pressure within ducts while optimizing airflow distribution. This algorithm has the potential to transform HVAC systems, ensuring minimal pressure loss, substantial energy savings, and heightened environmental sustainability.In summary, this paper represents a comprehensive exploration of the intricate relationships between particle deposition, pressure loss, and damper control within HVAC duct systems. By shedding light on the complex mechanisms governing these phenomena, the study contributes to the development of advanced strategies for optimizing energy efficiency in HVAC operations. Keywords: Photoresist, Particle Accretion, Film Formation, Eulerian Wall Film, Particle Deposition, CFD simulation, HVAC, Damper Control, Pressure Loss, Energy Efficiency. Figure 1

Impacts of Stefan Blowing on Thermophoretic Particle Deposition in Sisko Nanofluid Flow Over a Riga Plate with Soret and Dufour Effects

The proposed framework considers the thermosolutal Marangoni convective flow of Sisko [Formula: see text] nanofluid over a Riga surface with the effects of Stefan blowing and thermophoretic particle deposition. The phenomena of mass and heat are discussed in relation to Soret and Dufour impacts. Electrodes and magnets are arranged on a plate to make up the Riga plate. Since the fluid conducts electricity, the Lorentz force upsurges exponentially in the vertical direction. There are numerous possible uses for this study in different disciplines. The design and production of thin films, coatings, and nanostructured materials can be enhanced by knowledge of how nanoparticles settle onto surfaces under various fluid flow conditions. By optimizing fluid flow and particle deposition processes, engineering insights from this work can guide the development of more efficient heat transfer systems, such as heat exchangers and cooling technologies. The nonlinear governing PDEs are converted into nonlinear ODEs using appropriate transformations. The resultant system of highly nonlinear equations can be solved analytically by using the homotopy analysis method (HAM). The significance of factors on the flow, thermal, and concentration fields are thoroughly explained with the use of tables and figures. Higher Marangoni convection parameter in more effective heat and mass transport within the liquid as well as higher induced flows when the Marangoni convection parameter is increased. A more uniform distribution of these properties throughout the liquid is the result of decreasing temperature and concentration profiles.