Collection Of Particles Research Articles

Evaluation of Material Selection for Small Wind Turbine Blades Using the TOPSIS Method

When creating a wind turbine blade, the material choice is crucial. Small wind turbine blades can be made out of a variety of materials, including wood, metals, carbon fibre reinforced polymers, natural fibre reinforced polymers, glass fibre reinforced polymers, and nanocomposites. Low density, high strength, and a long fatigue life are three attributes that must be present in the material used to create turbine blades. The substance is additionally made to tolerate high aerodynamic drag, fatigue loads, and impacts from the environment including dust particulate collecting and humidity. The material used to make the turbine blades should have the aforementioned essential qualities, including low density, high strength, and long fatigue life. Additionally, the material is made to endure high aerodynamic drag, fatigue loads, and environmental effects including dust particle collection and moisture materials. In order to capture energy from moving air masses, rotor blade designs rely on the principles of lift or drag. The lift blade design generates a force that lifts the object perpendicular to the plane of motion using the same principle that allows aeroplanes, kites, and birds to fly. Low density, high strength, fatigue resistance, and damage tolerance are requirements for materials used to make wind turbine blades. Composite materials, or materials with an elevated component content, are used extensively in the construction of the blades. Top Rank by Similarity to the Ideal Solution (TOPSIS), a multi-criteria evaluation technique, makes use of numerous factors. The alternative must be the furthest away of the beneficial ideal solution (BIS) & the negative ideal solution (NIS) in order to be chosen. Topsis is built on this principle. The geometric gap between each choice and the most favourable option—that is, the option with the greatest score for each criterion—is calculated after a collection of alternatives is evaluated and the scores for all criteria are normalised. An analytical hierarchical process, the direct prioritisation approach, and other techniques can be utilised to calculate the value requirements according to the TOPSIS method. By using TOPSIS, parameters are thought to be steadily rising or decreasing. Alternate Parameters taken as Wood, Aluminium, epoxy based Carbon FRP (CFRPEP), epoxy based Glass FRP (GFRPEP), polypropylene based Glass FRP with (GFRPPP), epoxy based Cotton-Glass FRP (CGFRPEP), polypropylene based Cotton-Glass FRP (CGFRPPP), epoxy based FlaxGlass FRP (FGFRPEP), and epoxy based Sisal-Glass FRP with (SGFRPEP), plastic. Evaluation Parameters taken a Tensile Strength (MPa), Production Rate, Flexural Strength (MPa), Corrosion resistance, Blade Cost (USD), Setup Cost (USD), Density (kg/m^ {3}). From the result it is seen that epoxy based Carbon FRP (CFRPEP) got the first rank and Aluminium has the lowest rank. The first ranking epoxy based Carbon FRP (CFRPEP) is obtained with the lowest quality of Aluminium

Atomization Performance of Spray Nozzles and Their Influence on Fine Particle Collection in the Wet Electrostatic Precipitator

The wet electrostatic precipitator (WESP) is crucial for the ultra-purification of blast furnace gas in gas-fired generator units. To address issues like high water consumption, poor atomization leading to spark discharge, and uneven water mist distribution, a water mist testing system using a laser particle-size analyzer was established. Eight spray nozzles were tested to identify the optimal atomization performance and operating parameters. The effect of chemical agglomeration agents on nozzle atomization and particle capture efficiency was also examined. The results show that the atomization effect was the best when the operating water pressure was 0.5 MPa. The D50 of the blast furnace dust increased from 8.529 μm to 20.30 μm after electrostatic precipitation when the 1/8 rotating core nozzles were installed in the WESP, and the proportion of dust particles whose diameter is ≤5 μm decreased by 20.09% compared with the dust emitted from the inlet. The total dust removal efficiency reached 83.41%. With chemical agglomeration, the D50 reached 24.88 μm, and removal efficiency rose to 96.98%. Among the tested nozzles, the 1/8 rotating core nozzle was the most effective, combining superior atomization, maximum dust removal efficiency, and minimal water consumption, making it ideal for blast furnace gas purification.

Venus cloud catcher as a proof of concept aerosol collection instrument

We report on the proof-of-concept of a low-mass, low-power method for collecting micron-sized sulfuric acid aerosols in bulk from the atmosphere of Venus. The collection method uses four wired meshes in a sandwich structure with a deposition area of 225 cm2. It operates in two modes: passive and electrostatic. During passive operation, aerosols are gathered on the deposition surface by aerodynamic force. During electrostatic operation, a tungsten needle discharges a high voltage of − 10 kV at the front of the grounded mesh structure. The discharge ionizes aerosols and attracts them to the mesh by Coulomb forces, resulting in improved efficiency and tentative attraction of submicron aerosols. We describe the instrument construction and testing in the laboratory under controlled conditions with aerosols composed of 25%, 50%, 70%, 80%, 90% and 98%* concentration by volume of sulfuric acid, the rest water. We demonstrated the following: (i) both modes of operation can collect the entire range of sulfuric acid solutions; (ii) the collection efficiency increases steadily (from a few percent for water to over 40% for concentrated sulfuric acid) with the increased concentration of sulfuric acid solution in water in both modes; (iii) the relative improvement in the collection of the electrostatic mode decreases as the sulfuric acid concentration increases. We also demonstrated the operation of the instrument in the field, cloud particle collection on Mt. Washington, NH, and crater-rim fumaroles’ particle collection on Kīlauea volcano, HI. The collection rate in the field is wind-speed dependent, and we observed collection rates around 0.1 ml in low wind environments (1–2 m), and around 1 ml in stronger wind (7–9 m).

Effects of aggregate crushing and strain rate on fracture in compressive concrete with a DEM-based breakage model

This study looked at how breakable aggregates affected the mesoscopic dynamic behavior of concrete in the uniaxial compression condition. In-depth dynamic two-dimensional (2D) studies were conducted to examine the impact of aggregate crushing and strain rate on concrete’s dynamic strength and fracture patterns. Using a DEM-based breakage model, concrete was simulated as a four-phase material consisting of aggregate, mortar, ITZs, and macropores. The concrete mesostructure was obtained from laboratory micro-CT tests. Collections of spherical particles were used to imitate aggregate breakage of different sizes and shapes by enabling intra-granular fracturing between them. The mortar was described in terms of unbreakable spheres with different diameters. Compared to the mortar, the aggregate strength was always stronger. A qualitative consistency was achieved between the DEM results and the available experimental data. Concrete’s dynamic compressive strength rose significantly with strain rate and just somewhat with aggregate strength. The fracture process was impacted considerably by aggregate crushing and strain rate. The number of broken contacts grew with an increase in strain rate and a decrease in aggregate strength.

Effects of particle size on the magnetic cleaning system for manned lunar explorations

A magnetic cleaning system comprising a permanent magnetic roll with a non-magnetic sleeve and a particle collection component is a unique dust mitigation technology in lunar explorations. Enhanced cleaning performance can be achieved by optimal balancing of the forces applied to the particles. The effects of particle size on the capture and release performances were investigated through experiments using size-sorted particles of a lunar regolith simulant and a simple analysis of the force balance varying with the particle size. Experimental and calculated results clarified that the capture of the particles was predominantly facilitated by the magnetic force, while their release was primarily due to the centrifugal force. Although the release of captured particles smaller than 25 μm is one of the challenges in this system due to the adhesion force, this force also contributed to the capture of the small particles with lower magnetic permeability. This magnetic cleaning system, demonstrating its utility in removing particles not only from spacesuits but also from other equipment, achieved the capture and release rates exceeding 70 % and 90 %, respectively, when the simulant particles were dispersed on a flat surface. Moreover, the capture rate of simulant particles with higher magnetic permeability improved, reaching approximately 85 %.

Modeling of laser beam absorption on rough surfaces, powder beds and sparse powder layers

The energy transfer from a laser beam source to material surfaces with arbitrary geometrical features and variable surface roughness is the crucial step in many high-end engineering applications. We propose two models capable of predicting this energy transfer, applicable in different scenarios. The first is a high-fidelity numerical framework for the simulation of laser beam interaction with rough surfaces, which includes meshed geometry of arbitrary shape and material Lagrangian particles. The method discretizes the laser source as a collection of photon-type immaterial Lagrangian particles (Discrete Element Method) and is able to capture the effects of multiple reflections, angle-dependent reflectivity, and polarization change. Simulations were performed on a geometry reconstructed from a rough copper sample to reveal the impact of the polarization effects. This method is generally applicable to any surface where the effects of inelastic light scattering are not expected to play a significant role. The second model is a novel phenomenological correlation specifically designed to predict the effective reflectivity of sparse powder layers, which occur for example when metal vapor is recondensed and redeposited on the substrate during laser welding. The correlation is compared to the predictions obtained from the simulation framework and has been favorably compared to experimental data in a separate publication.

An experimental study on monitoring and early warning of spontaneous coal combustion fires using CPM

At present, the conventional indicator gas has a blank temperature interval in the monitoring of coal spontaneous combustion fire area, and the monitoring accuracy is easy to be interfered by wind flow, which leads to the inaccurate grasp of the situation of the fire area. To solve this problem, the characteristics of condensable particulate matter (CPM) released into the air during spontaneous combustion and heating are analyzed in this paper through a particle collection system. The results showed that the CPM captured by the system gradually increased when the coal temperature rose above 250℃, and the diameter was above 1um. After 300℃, the release of CPM increased significantly, which was more than 10 times that below 300℃. Test analysis showed that these CPMs were mainly phenols and polycyclic aromatic hydrocarbons, which accounted for 22 % and 37 % respectively after 300℃. CPM mainly comes from the pyrolysis stage and the early stage of combustion of coal. Aliphatic macromolecules and polycyclic aromatic compounds generated by pyrolysis are the precursors of CPM. Due to the limitation of oxygen diffusion, these compounds are released into the air due to insufficient oxidation and eventually form CPM. It is worth noting that the release amount and composition of CPM have a good correspondence with coal temperature. The research results can fill the temperature gap of monitoring fire situation by conventional gas, and help to improve the accuracy of monitoring, which is of great significance for the protection of coal resources and safe production.

Design of the electrode structure for the dust removal efficiency optimization of electrostatic precipitator

Abstract Air dust pollution prevention and control is a global environmental concern. Electrostatic precipitators (ESPs) play a crucial role in dust pollution control, and its electrode structure significantly affects plasma parameters and the movement of charged dust particles, which in turn influences the dust removal efficiency. This study focuses on optimizing the commonly used wire-plate dust removal device, experimental research is conducted first, revealing that the hole-hole electrode structure of an ESP exhibits higher peak currents at the same voltage compared to both plate-hole and plate-plate electrode configurations. For the removal efficiency of particles with a radius greater than 1 μm, the ESP with a hole-hole electrode structure performs better than those with plate-hole and plate-plate electrode structures. Moreover, the particle collection efficiency is positively correlated with particle radius, larger particles correspond to higher dust removal efficiency. Based on experimental findings, simulations are conducted to provide a deeper analysis and understanding of the dust removal mechanisms of ESPs. This paper primarily utilizes COMSOL Multiphysics numerical simulation software to simulate traditional wire-plate ESPs and a new wire-hole ESP. It explores the multiphysical characteristics of ESPs under different electrode structure configurations, and investigates in depth the impact of electrode structure on dust removal efficiency. The simulation results indicate that compared to flat collecting electrodes, porous collecting electrodes exhibit a significant increase in electric field intensity at the openings, and they have a lower surface charge density than flat plates, thereby reducing reverse corona phenomena. Ion wind affects the internal airflow dynamics of ESPs, thereby influencing their efficiency in capturing fine particulate matter. This negative impact of ion wind can be mitigated by introducing perforations in the collection plates.

An Adaptive Approach in Polymer-Drug Nanoparticle Engineering using Slanted Electrohydrodynamic Needles and Horizontal Spraying Planes.

The present study focuses on the adaptive development of a key peripheral component of conventional electrohydrodynamic atomisation (EHDA) systems, namely spraying needles (also referred to as nozzles or spinnerets). Needle geometry and planar alignment are often overlooked. To explore potential impact, curcumin-loaded polylactic-co-glycolic acid (PLGA) and methoxypolyethylene glycol amine (PEG)-based nanoparticles were fabricated. To elucidate these technological aspects, a horizontal electrospraying needle regime was adapted, and three formulations containing different polymeric ratios of PLGA: PEG (50:50, 75:25, and 25:75) were prepared and utilised. Furthermore, processing head tip geometries e.g.blunt (a flat needle exit) or slanted (a 45° inclination angle), were subjected to various flow rates (5 µL-100 µL). Successful engineering of curcumin-loaded polymeric nanoparticles (< 150nm) was observed. In-silico analysis demonstrated stable properties of curcumin, PEG and PLGA (molecular docking studies) and fluid flow direction towardsthe Taylor-Cone (also known as the stable jet mode), was shownby the assessment of fluid dynamics simulations in various needle outlets. Curcumin-loaded nanoparticles were characterised using an array of methods including Scanning electron microscopy, Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, as well as their contact angles, encapsulation efficiencies and finally release patterns. The discrepancy when spraying with blunt and angled needles was evidenced by electron micrographs and deposition patterns. Spraying plumes utilising slanted needles enhanced particle collection efficiency and distribution of resultant atomised structures. In addition to needle design, fine-tuning the applied voltage and flow rate impacted the electrospraying process. The coefficient of variation was calculated as 30.5% and 25.6% for blunt and angled needle outlets, respectively, presenting improved particle uniformity with the employment of angled needle tips (8-G needle at 25 µL). The interplay of processing parameters with the utilisation of a slanted exit at a capillary optimised the spray pattern and formation of desired nanoparticulates. These demonstrate great applicability for controlled deposition and up-scaling processes in the pharmaceutical industry. These advances elaborate on EHDA processes, indicating a more cost-effective and scalable approach for industrial applications, facilitating the generation of a diverse range of particle systems in a controlled and more uniform fashion.

Capture behavior of self-propelled particles into a hexatic ordering obstacle

Abstract Computer simulations are utilized to investigate the dynamic behavior of self-propelled particles (SPPs) within a complex obstacle environment. The findings reveal that SPPs exhibit three distinct aggregation states within the obstacle, each contingent on specific conditions. A phase diagram outlining the aggregation states concerning self-propulsion conditions is presented. The results illustrate a transition of SPPs from a dispersion state to a transition state as persistence time increases within the obstacle. Conversely, as the driving strength increases, self-propelled particles shift towards a cluster state. A systematic exploration of the interplay between driving strength, persistence time, and matching degree on the dynamic behavior of self-propelled particles is conducted. Furthermore, an analysis is performed on the spatial distribution of SPPs along the y-axis, capture rate, maximum capture probability, and mean-square displacement. The insights gained from this research make valuable contributions to understanding the capture and collection of active particles.

Experimental and Numerical Investigation of Slip Effect on Nanofiber Filter Performance at Low Pressures.

Nanofiber filters are widely used in air filtration applications due to their superior performance over microfiber filters. Velocity slip around nanofibers has been identified as a key factor contributing to their high figure of merit, yet its impact on filter performance, especially particle collection efficiency, remains unclear due to the difficulty in isolating the slip effect as the sole variable. This study combines experimental and simulation methods to investigate the slip effect by adjusting the air molecule mean free path, rather than varying fiber size as done in previous studies. Filter media with mean fiber sizes ranging from 16.2 to 0.084µm are utilized. An image-based regression method is developed to address the challenge of determining the solidity of thin nanofiber layers. The results show that the slip effect is enhanced as the testing pressure decreases, reducing pressure drop by less than 15% for microfiber filters and over 50% for nanofiber filters ≈100nm. The enhanced slip effect at low pressures (i.e., relatively low pressure compared to the ambient environment) significantly improves filtration efficiency, especially for particles larger than 100nm. It also proposes semi-empirical equations for predicting filter performance in slip and transition flow regimes.

Evaluation of salt particle collection devices for coastal metal storage facilities with natural ventilation

Abstract Stress corrosion cracking (SCC) is a potential threat to metal containers stored in coastal facilities utilizing natural ventilation due to sea salt particles in the airflow. This study investigates the applicability of low-pressure salt particle collection devices developed by the Central Research Institute of Electric Power Industry (CRIEPI) in Japan (reports N08050 and N11044) to natural ventilation systems in Taiwanese coastal storage facilities. We evaluate the capture efficiency and pressure drop of these devices compared to conventional stainless steel filters. The pressure loss of the collection devices was assessed using the CRIEPI model and compared with a handbook model, demonstrating high agreement. Capture efficiency analysis revealed a reduction rate of approximately 78% for the salt particle collection device. However, peak analysis indicated this reduction was primarily effective for particles exceeding 10.2 μm in diameter. Compared to stainless steel filters, the collection devices offer lower reduction efficiency but with a stable pressure drop and potentially lower maintenance costs. This study also emphasizes the need for optimizing salt particle reduction methods by considering the trade-off between capture efficiency and pressure drop.

Evaluation of testing face-mask filter samples with LAMP shows high rates of detection in pulmonary TB.

<sec><title>BACKGROUND</title>Detection of Mycobacterium tuberculosis (MTB) in bioaerosols derived from patients with active pulmonary TB is a potential alternative diagnostic method for patients with presumed TB who cannot expectorate sputum.</sec><sec><title>OBJECTIVE</title>To assess the efficacy of a bioaerosol particle collection method to capture MTB and diagnose TB.</sec><sec><title>METHODS</title>A mask-like filter holder (3D mask) with a water-soluble gelatine filter (GF) and one containing a water-insoluble polypropylene filter (PPF) were prepared. Eligible patients wore the 3D mask with GF or PPF within 3 days of starting anti-TB drugs. The GF and PPF filters were collected after 2 and 8 h. DNA was extracted from the filter samples and tested using loop-mediated isothermal amplification (LAMP).</sec><sec><title>RESULTS</title>Filter samples were collected from 57 and 20 patients with and without active pulmonary TB, respectively. The GF and PPF sensitivity was 76.2% and 83.3%, respectively. The specificity of both methods was 100%. Of the 57 patients diagnosed with non-expectorated sputum samples, including suction phlegm, gastric lavage, and bronchial lavage fluid, 55.6% and 50.0% were positive by GF and PPF, respectively.</sec><sec><title>CONCLUSION</title>We present a 3D mask filter sampling method for exhaled bioaerosol particles that can be used in clinical practice to diagnose patients with presumed TB.</sec>.

Microscale insights into deep bed membrane filtration: Influence of internal surface roughness

Deep bed filtration is widely applied in bioprocessing, virus filtration, and water purification to remove small impurities, such as particles or virus fragments. However, more needs to be understood about the parameters that influence particle capture and deposition. Detailed simulations and microfluidic filtration experiments with straight pores have been widely investigated, yet realistic membrane porosity features such as pore gradients and roughness have not been addressed in detail. The internal membrane morphology is assumed to have a strong effect on filtration performance. Therefore, this study introduces a new microfluidic membrane mimicking device (MMD) and methodology that analyzes spatio-temporal particle collections in a deep bed filtration MMD with gradually decreasing pore size toward the retentate side. The design allows us to systematically tailor an internal filter surface roughness to investigate its influence on differently sized soft particles and the consequences for filtration performance, in particular, particle capture. Optical investigation and quantitative evaluation show enhanced particle–pillar interactions for increased roughness. This results in a reduced penetration depth and reduced particle breakthrough. The modes of capture or filtration phenomena, such as pore blocking, bridging, or dendrite formation, differ significantly between smooth and rough membrane filter structures. In the case of rough inner filter surfaces, those phenomena lead to a less distinct decrease in volumetric flow, allowing a longer filtration process. The microfluidic study offers a detailed investigation of how microscale phenomena influence the filtration process. The results provide a fundamental understanding of microscale filtration effects based on roughness and, hence, motivate a tailoring of the internal membrane filter surface according to the filtration problem at hand.

Fermat-Weber location particle swarm optimization for cooperative path planning of unmanned aerial vehicles

This paper presents an effective algorithm, called the Fermat-Weber location particle swarm optimization (FWL-PSO), developed for cooperative path planning of Unmanned Aerial Vehicles (UAVs). Initially, FWL-PSO is constructed by harnessing the Fermat-Weber optimality to identify potential solutions. Within the framework of FWL-PSO, a collection of high-performing particles is established, determined by their respective fitness scores. Following this, the Fermat-Weber location of these elite particles is calculated to supersede the traditional global best, thereby augmenting the learning strategy of the standard PSO. As a result, this method enables the evolution of information while encouraging search diversity. Subsequently, FWL-PSO is employed for handling the interactions of multiple UAVs. In this context, the path planning for a group of UAVs is formulated as a Nash game that incorporates all cooperative interdependencies and safety conditions. The algorithm is then integrated to solve the optimization problem for achieving the Nash equilibrium. To assess its efficacy, extensive simulations and experiments are conducted across a variety of path-planning scenarios. Comparative analyses between FWL-PSO and existing PSO variants underscore the enhanced efficiency and reliability of our proposed approach.

3D printed Ti3C2@Polymer based artificial forest for autonomous water harvesting system

The escalating scarcity of freshwater resources presents significant challenges to global sustainability, demanding innovative solutions by integrating cutting-edge materials and technologies. Here we introduce an autonomous artificial forest (3D AF) for continuous freshwater acquisition. This system features a three-dimensional (3D) architecture incorporating a carbon nanofiber (CNF) network and MXene@polypyrrole (Ti3C2@PPy), enhancing surface area, light absorption, heat distribution, and surface wettability to improve solar vapor generation and fog collection efficiency. The autonomous operation is facilitated by an integrated photothermal actuator that adjusts to the day and night conditions. During daylight, the 3D AF tilts downward to maximize solar exposure for water evaporation, while at night, it self-adjusts to optimize fog particle collection. Notably, our device demonstrates the ability to harvest over 5.5 L m−2 of freshwater daily outdoors. This study showcases the potential of integrating advanced materials and technologies to address pressing global freshwater challenges, paving the way for future innovations in water harvesting.

Aerodynamic Size-Dependent Collection and Inactivation of Virus-Laden Aerosol Particles in an Electrostatic Precipitator.

Electrostatic precipitators (ESPs) may enable high particle collection efficiency with minimal pressure drop in HVAC systems. However, studies of pathogen collection and inactivation in ESPs at medium to higher flow rates are limited. Here, a single-stage, wire-plate ESP operated at flow rates of 51 and 85 m3 h-1 was used to study the removal of virus-laden aerosol particles for three different airborne viruses: (1) bovine coronavirus (BCoV), (2) influenza A virus (IAV), and (3) porcine reproductive and respiratory virus (PRRSV). Size-resolved measurements of collection efficiency were obtained using Andersen cascade impactors (ACI) sampling upstream and downstream of the ESP. All measurements were analyzed based on three distinctive but complementary methods: (1) fluorimetry to assess physical collection, (2) RT-qPCR to assess viral RNA concentrations and (3) virus titration to assess virus viability. In general, log reductions by virus titration were highest followed by those from RT-qPCR, and last fluorimetry, suggesting that a portion of virus may be potentially inactivated in flight in the ESP. An effective migration (deposition) velocity ranging from 3.10 to 10.05 cm s-1 was also determined using the spatially resolved measurements of virus collection on the ESP plates.

Proteomic Characterization of Transfusable Blood Components: Fresh Frozen Plasma, Cryoprecipitate, and Derived Extracellular Vesicles via Data-Independent Mass Spectrometry.

Extracellular vesicles (EVs) are a heterogeneous collection of particles that play a crucial role in cell-to-cell communication, primarily due to their ability to transport molecules, such as proteins. Thus, profiling EV-associated proteins offers insight into their biological effects. EVs can be isolated from various biological fluids, including donor blood components such as cryoprecipitate and fresh frozen plasma (FFP). In this study, we conducted a proteomic analysis of five single donor units of cryoprecipitate, FFP, and EVs derived from these blood components using a quantitative mass spectrometry approach. EVs were successfully isolated from both cryoprecipitate and FFP based on community guidelines. We identified and quantified approximately 360 proteins across all sample groups. Principal component analysis and heatmaps revealed that both cryoprecipitate and FFP are similar. Similarly, EVs derived from cryoprecipitate and FFP are comparable. However, they differ between the originating fluids and their derived EVs. Using the R-package MS-DAP, differentially expressed proteins (DEPs) were identified. The DEPs for all comparisons, when submitted for gene enrichment analysis, are involved in the complement and coagulation pathways. The protein profile generated from this study will have important clinical implications in increasing our knowledge of the proteins that are associated with EVs derived from blood components.

Influence of coconut and castor oil coating on engine intake non-woven filter performance

PurposeThis research focuses on the development and characterization of oil-wetted spun-bonded polypropylene (PP) non-woven filters for improved air intake systems in automobiles. The study aims to enhance engine performance, durability, fuel economy and emission reduction by addressing key aspects such as contaminants filtration efficiency, loading capacity, pressure drop, temperature performance and longevity.Design/methodology/approachThe research methodology involves the utilization of textile fabrics, particularly oil-wetted spun-bonded PP non-woven filters, renowned for their effective particle collection capability from intake air. Experiments were conducted using a Box–Behnken design with three variables – oil concentration, areal density and dust quantity – each at three different levels to establish correlations with the filter’s dust holding capacity (DHC) and pressure drop.FindingsThe findings indicate that immersing particles in oil-coated medium significantly enhances the filter’s DHC. Notably, castor oil as a coating demonstrates remarkable results, with a 97.53% increase in DHC and a high particulate matter filtration efficiency of 94.12%.Originality/valueThis study contributes to the originality of research by emphasizing the importance of oil density in determining the filter’s DHC and filtration efficiency. Furthermore, it highlights the superiority of castor oil over coconut oil-coated filter media, advancing air intake and/or filter systems for automotive engines.

Development of a methodology for studying microbiological contamination of office indoor air by analyzing air handling unit filters - Application to a low-energy building

Bioaerosols can alter the air quality, affecting differently people depending on their health status. Methods to sample bioaerosols are limited in terms of sampling time and air volumes. This study evaluated a new methodology to sample airborne microorganisms in buildings, using the air handling unit (AHU) filters and filtration media sampling discs (FMSD). Filtration media with FMSD of different natures were tested at the laboratory, and characterized by their air permeability, particle collection efficiency and the airflow distribution on their surface. Filtration media with FMSD of the same nature had best properties with a sampling particle efficiency of the FMSD of 50 %. This sampling methodology was applied on a building AHU, and FMSD were collected each month during one year. Airborne microorganisms collected by the FMSD were analyzed by culture and nucleic acids based methods (qPCR and Next-Generation sequencing). FMSD methodology gave results for all of those identification methods. Most of the bacteria orders identified by 16 S sequencing were Rhodobacterales (Paracoccus), Pseudomonadales and Cyanobacteria. For fungi, the most represented orders were Agaricales, Polyporales and Hymenochaetales. This sampling methodology has also made it possible to detect small size airborne microorganisms like viruses including two Coronaviruses. This study has shown the potential of using AHU filters to sample the airborne microorganisms in buildings.