10,062 results on '"AIR filters"'
Search Results
2. Preparation, characterization and antibacterial properties of hydro-charged melt-blown nonwovens coated with an N-halamine.
- Author
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Liu, Chao, Shi, Jiayan, Luo, Fengxiang, and Zhang, Xing
- Subjects
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ESCHERICHIA coli , *AIR filters , *PRESSURE drop (Fluid dynamics) , *POLYPROPYLENE , *FIBERS - Abstract
Air filtration materials can protect humans from the invasion of airborne pathogens. However, pathogens intercepted by air filters can survive in fibrous materials and pose a threat to human health if they proliferate in large quantities. Therefore, in this work, modified hydro-charged polypropylene (PP) melt-blown nonwovens with antibacterial properties were prepared to reduce the infection rate during the filtering process. Firstly, PPm electret melt-blown nonwovens containing 5 wt% electret masterbatch PP-MgSt were prepared by the melt-blown process and hydro-charging technology. Then, an N-halamine compound, 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC), was used for antibacterial modification. MC was evenly coated on the surface of the melt-blown fibers by spraying and dipping processes to obtain PPm/MC-s and PPm/MC-d melt-blown samples, respectively. The PPm/MC-s and PPm/MC-d samples demonstrated excellent antibacterial properties, killing 99.99% of E. coli and S. aureus in 5 and 10 minutes of contact times, respectively. However, the filtration results indicated that the surface coating treatment reduced the filtration efficiency of both samples to varying degrees. Specifically, the filtration efficiency of PPm/MC-s decreased from 99.64% to 94.77%. Due to the excessive use of ethanol during the PPm/MC-d modification process, more electret charges escaped, resulting in a significant decrease in filtration efficiency to 69.66%. Comprehensive analysis proposed that melt-blown nonwovens that have already been processed and formed are more suitable for MC antibacterial modification by spraying method. The modified melt-blown samples can provide strong antibacterial effects while maintaining high filtration efficiency and low pressure drop. This work provides a feasible industrialized antibacterial modification method for formed melt-blown filtration nonwovens, which can further improve the protective performance of traditional filter products. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Study on the Influence of Walnut Shell Coarse Particles on the Slurry Permeation and the Air Tightness of Filter Cake.
- Author
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Dong, Qi, Liu, Tao, Wang, Yuan, Liu, Sijin, and Wen, Letian
- Subjects
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AIR filters , *WALNUT , *PERMEABILITY , *SAND , *EXCAVATION - Abstract
Slurry shields rely on the formation of a compact filter cake to maintain excavation face stability and ensure construction safety. In strata with high permeability, significant slurry loss occurs, making filter cake formation and air tightness maintenance challenging. In this study, light organic walnut shell was selected as an additive coarse particle material for slurry. Slurries incorporating two types of coarse particles, sand and walnut shell, were prepared, and tests on slurry permeation and air tightness of the filter cake were conducted in three different strata. The results indicate that the addition of coarse particles effectively improves filter cake formation and air tightness in high-permeability strata. It is essential to use graded particles in highly permeable strata, with controlled maximum and minimum particle sizes. As the content of coarse particles increases, the air tightness of the filter cake initially increases and then decreases. Notably, the air tightness of filter cakes containing walnut shell is superior to those containing sand. Replacing sand with walnut shell as a slurry plugging material enhances filter cake quality in high-permeability strata. For highly permeable strata with a permeability coefficient greater than 1.0 × 10−3 m/s, an addition of 30 g/L to 40 g/L is recommended. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Finite difference analysis for entropy optimized nanomaterial Darcy-Forchheimer flow with homogeneous and heterogeneous reactions.
- Author
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Hayat, T., Shinwari, W., Abbas, Z., Momani, S., and Zia, Q.M.Z.
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CHEMICAL processes ,COOLING towers ,FINITE differences ,FERROUS oxide ,AIR filters - Abstract
Hybrid nanoliquids are not underestimated for their involvement in microelectronics, transportation, coolant processes, ships, biological processes and power generation. Hence motivation for current work is to examine homogeneous-heterogeneous reactions in entropy optimized flow by curved sheet stretched with nonlinear velocity. Trihybrid nanoliquid is synthesized through 2 % of ferrous oxides (F e 3 O 4 ) , 2 % of silver (A g) and 2 % of copper (C u). Kerosene oil is employed as the base fluid. These specific kinds of nanoparticles are taken into consideration because of their numerous applications in heat dissipation, air filters, dynamic sealing, biosensors and catalysts process. Kerosene oil may have applications in many different domains such as energy storage, cleaning agent, portable heaters, fuel additive and industrial lubricants. Darcy-Forchheimer model is employed. Analysis in presence of radiation, dissipation, Ohmic heating, entropy generation and heat generation/absorption are organized. Unlike the previous considerations, the thermal expression here consists of impacts through Darcy-Forchheimer relation. Adequate transformations are implemented. Computations have been arranged by applying finite difference technique (FDM) using MATLAB. Quantities for physical interest are addressed. The presented analysis may have relevance for solar systems, chemical reacting processes, cooling towers and polymer data processes. The conclusions are also organized for important key findings. It is noticed that trihybrid nanomaterial has more entropy rate when compared with hybrid and classical nanoliquids when volume fraction is chosen as 2 % for trihybrid fluid. It is proposed that the ability to transfer heat is enhanced when nanoparticles are added to conventional fluids. Decay in concentration is noticed for both homogeneous and heterogeneous parameters. Reduction for Bejan number is noticed through homogeneous diffusion factor. Comparison with previous study is also presented and found great consensus between them. [ABSTRACT FROM AUTHOR]
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- 2024
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5. 3D Porous Nanocellulose Based Filter from Palm Bunch Using Tert‐Butyl Alcohol‐Assisted Pore Inducive Technique for Airborne Particulate Matter Retention.
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Jahir Khan, Mohd, Chaipanya, Ratanaporn, Suksomboon, Sudarat, Sonyeam, Janejira, Posoknistakul, Pattaraporn, Charnnok, Boonya, Pongchaikul, Pisut, Laosiripojana, Navadol, Wu, Kevin C.‐W., and Sakdaronnarong, Chularat
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CHOLINE chloride ,AIR filters ,PARTICULATE matter ,PRESSURE drop (Fluid dynamics) ,LACTIC acid - Abstract
Environmental hazards, especially particulates, and microbiological pollutants, have resulted in significant negative impacts on human health. In this study, 3D biodegradable cellulose filters were made from nanocellulose and tested for the removal efficiency of airborne particulates. Cellulose was first extracted from palm empty fruit bunches (EFBs) using green Deep Eutectic Solvents (DESs) under moderate temperature and then homogenized at high pressure to produce cellulose at the nanoscale size. Three types of renewable choline chloride (ChCl)‐based DESs were used: lactic acid, 1,3‐butanediol, and oxalic acid. The maximum cellulose yield from DES pretreatment was 38.78 % based on raw EFB (100 % cellulose yield based on cellulose in EFB) with ChBu60 C and the maximum nanocellulose yield was 68.49 % based on cellulose in EFB with ChLa80 C after 12‐pass high pressure homogenization. The cellulose air filter was fabricated using tert‐butyl alcohol (tBuOH) solvent exchanged under freeze‐drying conditions and characterized by different state‐of‐the‐art techniques. It was shown that the ChBu80 C filter had the lowest pressure drop (10.16 mmH2O or 2.07 mmH2O cm−2) and the maximum particle filtration efficiency (32.51 % for 0.1 μm and 93.63 % for 1.0 μm particles). The process simulation and techno‐economic analysis were performed for nanocellulose production and air filter fabrication to select the most feasible technology. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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6. Multi-Disciplinary Optimization of UV-C Filter for Air Disinfection.
- Author
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Carli, Igor, Poloni, Carlo, Clarich, Alberto, and Russo, Rosario
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OPTIMIZATION algorithms ,RAY tracing ,AIR filters ,AIR flow ,AIR masses - Abstract
Featured Application: To contain the diffusion of pathogens through air, a UV-C filter is optimized by CFD and ray tracing analysis guided by an MDO platform. Because of the recent COVID-19 pandemic, the problem of preventing and containing the diffusion of pathogens spread through air has become a main topic of research. The problem is particularly important for specific environments, such as dental or other medical practices, where the aerosol treatments in open-mouth patients, combined with closed and crowded rooms, raise the risk of infection. As an efficient countermeasure, in this study we propose a solution that is able to remove the risk at the source, through the aspiration of the aerosol and the neutralization of the bacterial load by means of a UV-C LED filter, which releases the sterilized air in the environment. To maximize the efficiency of the solution, in this study we performed a numerical multi-disciplinary optimization (MDO) of the filter, coupling numerical simulations of multiple disciplines (CFD and electromagnetics) by the process automation and optimization environment modeFRONTIER of ESTECO. Geometrical parameters of the filter are updated for each candidate solution proposed by the optimization algorithm, and their performance in terms of viral neutralization efficiency and air mass flow rate are evaluated by the simulations, until the optimal solution is found. The methodology and results of the study are presented. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Application of Biomass-Based Triboelectrification for Particulate Matter Removal.
- Author
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Chen, Hui, Wu, Yabo, Ma, Zheng, Wu, Yefei, Ding, Zhaodong, and Yin, Lianghong
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AIR pollutants , *TRIBOELECTRICITY , *PARTICULATE matter , *ELECTROSTATIC fields , *AIR filters - Abstract
Electrostatic fields are crucial for achieving the highly efficient filtration of airborne pollutants. However, the dissipation of static charges over time, especially under humid conditions, limits their practical application. In this study, we present a self-charging air filter (SAF) powered by a triboelectric nanogenerator (TENG). This SAF is integrated into a commercial mask, termed SAFM, which can effectively capture and degrade airborne pollutants without requiring an external power source. By leveraging the triboelectric effect during breathing, the TENG within the SAFM continuously replenishes static charges, maintaining the triboelectric field. The system employs a cellulose aerogel/Ti3C2Tx composite as the electron donor and an esterified cellulose-based electrospun nanofiber as the electron acceptor. Remarkably, the triboelectric field significantly enhances filtration performance, with the SAF achieving up to 95.7% filtration efficiency for particulate matter as small as 0.3 μm. This work underscores the potential of TENG-powered triboelectric fields in the development of multifunctional, human-machine interactive facemasks. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Modeling the Geometry and Filter Composite of the Air Cleaner.
- Author
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Olszewska, Pola Kalina, Pinkos, Justyna, Borkowski, Dominik, and Jablonski, Maciej
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SIMULATION software , *GEOMETRIC modeling , *AIR pollution , *NONWOVEN textiles , *AIR filters - Abstract
Air pollution is currently the most significant environmental factor posing a threat to the health and lives of European residents. It is a key cause of poor health, particularly respiratory and cardiovascular diseases. The primary aim of the study was to numerically determine the impact of the air purifier model's geometry on the distribution of air within a room and to conduct experimental tests on the filtration efficiency and preliminary antibacterial activity of filtration composites. The scope of the work included designing an air purifier model in the form of a pendant lamp and performing computer simulations in Ansys software to identify the optimal shape. The experimental research focused on developing filtration composites consisting of nonwoven fabric with an active hydrosol layer, meltblown nonwovens and a carbon filter. The study results showed that the SMMS composite with 50% thyme and carbon nonwoven exhibited the highest filtration efficiency for both small and large particles. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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9. Use of Portable Air Cleaners in Washington State Schools: A Qualitative Analysis Based on the Technology Acceptance Model.
- Author
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Carmona, Nancy, Seto, Edmund, Hayward, Lisa, Tan, Shirlee, Lee, Sinang, Kemperman, Brandon, Truong, Jenna, and Austin, Elena
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INDOOR air pollution prevention , *HIGH schools , *HEALTH literacy , *VENTILATION , *QUALITATIVE research , *HEALTH attitudes , *HUMAN services programs , *EXECUTIVES , *AIR filters , *INTERVIEWING , *LOGISTIC regression analysis , *INVESTMENTS , *DESCRIPTIVE statistics , *SURVEYS , *THEMATIC analysis , *EQUIPMENT maintenance & repair , *MEDICAL equipment , *TECHNOLOGY , *RESEARCH methodology , *STUDENT health , *RESPIRATORY protective devices , *INTENTION , *SENTIMENT analysis - Abstract
BACKGROUND: The US government allocated over $2.5 billion in "Elementary and Secondary School Emergency Relief (ESSER)" funds to Washington State for COVID‐19 response and ventilation improvements. Despite available funding, gaps persist in supporting schools to successfully use portable air cleaners (PACs). We evaluated PAC needs within King County, Washington and characterized factors influencing schools' purchase and use of PACs. METHODS: Public Health—Seattle & King County (PHSKC) assessed school's ventilation systems and IAQ improvements through a survey (N = 17). Separately, semi‐structured interviews (N = 13) based on the technology acceptance model (TAM) were conducted with school personnel. A thematic analysis using inductive and deductive coding was conducted and logistic regression models assessed the predictive capability of the TAM. RESULTS: The PHSKC survey findings informed our recommendations. Positive attitudes, knowledge, and beliefs in ease of use and effectiveness of PACs were facilitators to PAC use. While barriers included a lack of training, education, and concerns about PAC maintenance and sustainability. TAM constructs of perceived usefulness (PU) and perceived ease of use (PEU) were predictive of having the intention to use PACs in schools. CONCLUSIONS: There is a critical need for solutions to circumvent challenges to implementing PACs in schools. This characterization provides insight for promoting PAC use in IAQ‐impacted schools. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Emergency Knowledge Translation, COVID-19 and indoor air: evaluating a virtual ventilation and filtration consultation program for community spaces in Ontario.
- Author
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Katz, Amy, Li, Tianyuan, James, LLana, Buhariwala, Pearl, Osei-Twum, Jo-Ann, Siegel, Jeffrey, and O'Campo, Patricia
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INDOOR air quality , *COMMUNITY-based programs , *ENGINEERING education , *INFECTION prevention , *AIR filters - Abstract
Background: An October, 2021 review of Public Health Ontario's COVID-19 guidance for congregate settings such as shelters and long-term care homes demonstrated that this guidance did not include references to ventilation or filtration. In April 2022, an interdisciplinary team with expertise in indoor air quality (IAQ), engineering, epidemiology, community programming and knowledge translation launched a virtual ventilation and filtration consultation program for community spaces in Toronto, Ontario. The program gives people working in community spaces direct access to IAQ experts through 25-min online appointments. The program aims to help reduce the risk of COVID-19 transmission in community spaces, and was designed to help compensate for gaps in public health guidance and action. Methods: Representatives from participating organizations (n. 27) received a link to an online survey via email in April 2023. Survey questions explored the impacts of the program on topics such as: purchase and use of portable air filters; maintenance and use of bathroom fans; and, maintenance and modification of HVAC systems. Survey participation was anonymous, and no demographic information was collected from participants. Results: Representatives from 11 organizations completed the survey (40%). Of those who responded, nine (82%) made changes as a result of the program, with eight (73%) making two or more changes such as purchasing portable air filters and increasing routine maintenance of HVAC systems. Conclusions: When presented with brief access to expert support and tailored plain language guidance, people working in community spaces increased their use of ventilation and filtration strategies for COVID-19 infection prevention and control. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Modification of melt-blown polypropylene filters with spent green tea-mediated green synthesis of nanosilver for antibacterial activities and air purification.
- Author
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Srikhao, Natwat, Kasemsiri, Pornnapa, Srichiangsa, Natnaree, Souvanh, Mutjarin, Kidtang, Suteeporn, Jarernboon, Wirat, Okhawilai, Manunya, Uyama, Hiroshi, and Chindaprasirt, Prinya
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AIR purification , *AIR filters , *GREEN tea , *POLYVINYL alcohol , *TEA extracts - Abstract
Air pollution containing microorganisms presents a significant risk to human health. It is crucial to create air filters that are highly efficient for air purification and conducive to human health. Hence, this work aims to develop a filter based on melt-blown polypropylene (PP) spray-coated with green-synthesized silver nanoparticles (AgNPs). A bio-reducing agent from extracted spent green tea (SGT) was used in the AgNPs synthesis. Polyvinyl alcohol cross-linked with citric acid was used as a binder in spray coating. Effects of silver nitrate (AgNO3) concentrations, viz. 50, 100, and 150 mM, were investigated on AgNP formation and properties of spray-coated PP filter. Based on the results, the spray-coated PP filter with synthesized AgNP at 100 mM AgNO3 (AgNPs-100) showed the highest inhibition zones of both Gram-positive and Gram-negative bacteria. The tensile strength of the spray-coated PP filter with AgNPs ranged from 1309–1478 kPa, which was higher than that of the neat PP filter. The particle filtration efficiency of the spray-coated PP filter with AgNPs-100 for various particle sizes was enhanced by 27.95–447.04% compared to the neat PP filter. Moreover, the particle filtration efficiency of the spray-coated filter with AgNPs-100 was higher than 97% for particles of 0.3 μm, including PM1.0 and PM2.5. Therefore, the proposed spray-coated PP filter had a high potential to be a promising disinfecting filter for biomedical and hygienic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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12. Health benefits to vulnerable populations by meeting particle-level guidelines inside schools with different ventilation conditions.
- Author
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Rathi, Shubham, Goel, Anubha, Jain, Supreme, and Sreeramoju, Rushyendranath
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VENTILATION , *SCHOOL environment , *ENVIRONMENTAL monitoring , *HEALTH impact assessment , *SCHOOLS , *AT-risk people , *AIR filters , *DESCRIPTIVE statistics , *LUNG diseases , *PARTICULATE matter , *DISEASE risk factors - Abstract
We conducted simultaneous real-time measurements for particles on the premises of four schools, two of which were naturally ventilated (NV) and two mechanically ventilated (MV) in Kanpur, India. Health to school children from reduced particle levels inside classrooms simulated to the lowest acceptable levels (ISHRAE Class C: PM10 ≤ 100 µg/m3 & PM2.5 ≤ 25 µg/m3) using air filters were examined. Lung deposition of particles was used as a proxy for health impacts and calculated using the MPPD model. The particle levels in all classrooms were above the baseline, with NV classrooms having higher particle masses than MV classrooms: 72.16% for PM1, 74.66% for PM2.5, and 85.17% for PM10. Our calculation reveals a whooping reduction in particles deposited in the lungs (1512% for PM10 and 1485% for PM2.5) in the case of the NV classrooms. Results highlight unhealthy air inside classrooms and suggest urgent interventions, such as simple filtration techniques, to achieve acceptable levels of particles inside schools. [ABSTRACT FROM AUTHOR]
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- 2024
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13. FILTECH 2024: Preview.
- Subjects
CHEMICAL processes ,MATERIALS science ,SCANNING electron microscopes ,EDIBLE fats & oils ,MANUFACTURING processes ,AIR filters - Published
- 2024
14. Non-Woven Fabric Filter Materials Used in Public Buildings for Filtering Particulate Matter Experience Performance Changes under Ultrasonic Cleaning Based on Dual Carbon Target.
- Author
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Xue, Tao, Zhang, Xin, Cheng, Ping, Sun, Fenggang, Liu, Fuquan, and Yu, Tao
- Subjects
PARTICULATE matter ,NONWOVEN textiles ,INCINERATION ,PUBLIC buildings ,REFERENCE values ,AIR filters ,DUST - Abstract
The long-term use of air filters causes dust to accumulate on their surfaces or fill in the fibers of their internal filtering materials over time, thereby greatly reducing their effectiveness; therefore, the cleaning and replacement of air filter materials in public buildings are of great concern. The most commonly used non-woven fabric materials currently on the market are taken as the research object for this work, in which experiments are conducted on ultrasonic cleaning parameters, cleaning performance, regeneration effects, etc. The results showed that the best cleaning performance was achieved when the ultrasonic cleaning parameter was set to 120 W, and the cleaning time to 11.2 s, with a significant effect on particulate matter with a particle size of less than 2.5 μm. Under the premise of repeated dust containment, when PM
10 , PM2.5 , and PM1.0 are cleaned nine, six, and seven times, respectively, the filtration performance for these particles can also recover to over 85% of the performance of the fresh filter material before cleaning; however, after ten ultrasonic cleanings, the filtration resistance decreased within the range of 4.6~20.7 Pa. In this study, we aim to effectively reduce the replacement of old filters and the generation of incineration pollution, thereby reducing carbon-dioxide-equivalent emissions and providing a reference value for achieving the efficient utilization of filter materials in public buildings under the dual carbon target. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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15. Performance analysis of an electromechanical air purifier for particulate matter removal in large rooms.
- Author
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Sukoum, Jatuporn, Laokawee, Jarukit, Boonyung, Wanarut, Yawooti, Artit, Katongtung, Tossapon, and Tippayawong, Nakorn
- Subjects
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AIR pollution , *HEPA filters , *AIR analysis , *RESPIRATORY diseases , *LUNG cancer , *AIR filters , *INDOOR air quality - Abstract
Many countries, including Thailand, are grappling with air pollution, especially concerning particulate matter smaller than 2.5 µm (PM2.5). This fine particulate air pollutant has the potential to cause a range of respiratory diseases in humans, such as lung cancer and chronic airway inflammation. During high PM2.5 episodes, there is a specific concern about indoor air quality in enclosed spaces, especially for young children and the elderly who seek refuge indoors to avoid direct exposure. Air purifiers have become indispensable devices for mitigating PM2.5 levels in indoor air. However, most commercially available high-performance air purifiers are typically designed for small rooms and come equipped with high-efficiency particulate-free air (HEPA) filters, which can be expensive and have a relatively short lifespan. In this study, a high-efficiency air purifier designed for large room areas was developed, employing a combination of electrostatic and mechanical filtration through a compact electrostatic precipitator and a normal-grade filter in series. Testing was done to evaluate the filtration performance of this system within a sealed 200 m3 room, comparing it with popular commercially available air purifiers. The results indicated that our system achieved a filtration efficiency of over 90%, comparable to existing models, but with a higher clean air delivery rate. The electrostatic technique, when combined with the normal-grade filter, demonstrated enhanced PM2.5 removal. Our device managed to reduce indoor PM2.5 concentrations by 90% within 25 minutes, whereas single-stage air purifiers equipped with HEPA filters typically took about 45 minutes or more. This hybrid electromechanical filtration system has been shown effective and holds promise for improving indoor air quality in larger rooms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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16. The effectiveness of using HEPA filters in reducing the number of airborne bacteria in the operating room area.
- Author
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Soleha, Tri Umiana, Oktafany, Ayu, Putu Ristyaning, and Nafisah, Andi
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HEPA filters , *OPERATING rooms , *AIR filters , *PATHOGENIC microorganisms , *BACTERIAL colonies - Abstract
Nosocomial infection is a high potential infection that can occur in the operating room. High Efficiency Particulate Air (HEPA) is a folding mechanical air filter that in theory can remove at least 99.97% of dust, pollen, mold, bacteria and airborne particles measuring 0.3 microns (μm). Its effectiveness in capturing and retaining various disease-causing microorganisms with the same particle size is well known. Installing a HEPA filter above the ventilation grille or portable use to filter the air is the best solution to reduce the risk of spreading nosocomial infections. The purpose of this study is to determine the effectiveness of using a HEPA filter in reducing the number of bacteria in the air in the operating room area of RS "X" Bandar Lampung. This research was conducted on 10 samples of airborne bacteria in the operating room of a hospital in Lampung under 2 conditions consisting of counting the number of colonies growing on Plate Count Agar (PCA) media, Gram staining, culture on Blood Agar Plate and Mac Conkey Agar media, and biochemical tests such as catalase test and culture on Mannitol Salt Agar (MSA) media. The number of bacterial colonies at rest without a HEPA filter at 5 petri placement points was 91 with an air germ number of 16.99 CFU/m³. While the number of bacterial colonies at rest with a HEPA filter at 5 petri placement points was 9 with an average of 1.68 CFU/m³. Based on research, there has been a significant reduction in the number of airborne bacteria when HEPA filters are placed in the operating room. There is effectiveness of the use of a HEPA filter in reducing the number of bacteria in the air of the operating room area in Hospital. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Design and development of auto oxygen concentrator with SOS alert for hiking people.
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Chandrasekaran, G., Sudha, S., Kumar, N. S., Kalaiselvi, K. T., Sadesh, S., and Arun, S. B.
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NASAL cannula , *AIR filters , *DYSPNEA , *RECREATION , *HOSPITAL patients - Abstract
Trekking is a popular recreational activity. Hiking is popular among many people. Out-and-back, destination, and loop walks are the most prevalent types of walks. There is no such thing as an "eternal voyage." Trekking is more challenging than hiking, requiring the navigation of diverse and frequently harsh situations. Hiking is becoming a more popular pastime. Less oxygen is present at higher altitudes. Hikers' oxygen levels are constantly monitored to obtain oxygen immediately. A suffocating person does not receive oxygen during the early procedure. Oxygen concentrators can help people who have difficulty breathing. Many people who have breathing problems use an oxygen generator. After oxygen has been concentrated, it can be administered to patients via a pulse-dose or constant-stream system. Nitrogen is taken from the air using filters and sieve beds, and clean oxygen is added by changing the oxygen concentration and amount using the computer display. A mask or nasal cannula supplies oxygen directly into the airways. A concentrator's oxygen production rate is measured in liters per minute. Individuals can be tracked down using GPS. You can find out where people are by using GPS data. This can shorten the time it takes to save a patient and get them to a hospital. This position is comparable to the COVID-19 scenario, in which patients with Corona who have low oxygen levels are automatically given oxygen. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Review to Multifunctional Air Purification Systems: Technology Combinations and Evaluations.
- Author
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Jing Wu and Lexuan Zhong
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LINEAR free energy relationship , *AIR quality management , *EMERGING contaminants , *AIR purification , *INDOOR air quality , *AIR filters , *MICROBIOLOGICAL aerosols - Published
- 2024
19. ASHRAE Standard 241 and Graphene Silver-Coated MERV-A 9-A Filters: A Case Study.
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Sridhar, Deepak, Owen, Kathleen, Shacklock, Ryan, and van der Kuur, Colin
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OFFICE occupancy , *AIR quality standards , *INDOOR air quality , *NATURAL ventilation , *AIR flow , *AIR filters - Published
- 2024
20. Back in Tune.
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Beard, David
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ELECTRIC automobiles , *RACING automobiles , *AUTOMATIC automobile transmissions , *AIR filters , *TEMPERATURE control - Abstract
CarBahn, founded by Steve Dinan, offers powertrain and chassis tuning for BMW vehicles, aiming to recreate the high-performance experience of Dinan's previous tuned-up BMWs. The CarBahn CB3 M4 package boosts the BMW M3/M4 Competition xDrive models to 591 horsepower and 575 pound-feet of torque at the crank, with the option to increase to 735 horsepower with additional upgrades. The package includes engine enhancements, suspension modifications, and aesthetic upgrades, resulting in improved acceleration, handling, and overall performance. Dinan's tuning approach focuses on adjusting target torque to optimize power output while ensuring engine safety and performance. [Extracted from the article]
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- 2024
21. POLARIS 2025 RANGER XP 1000 NORTHSTAR ULTIMATE.
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AUTOMOBILE seats ,INFLUENCER marketing ,AIR filters ,POWERSPORTS dealers ,RETAIL industry - Abstract
Polaris has recently announced upgrades to its 2025 Ranger XP 1000 line, offering improvements in capability, comfort, and durability. The NorthStar Ultimate edition includes features such as a 4500-pound winch, larger bumper, increased ground clearance, and a new roof. Additional upgrades include revised suspension tuning, electronic power-steering assist maps, and a new interior with more storage. The NorthStar Ultimate also offers an audio system and trail-map database. The article praises the vehicle for its agility, handling, stability, work capabilities, and comfortable cabin. The price range for the 2025 Ranger XP 1000 models starts at $20,999 and goes up to $33,599. [Extracted from the article]
- Published
- 2024
22. A BREATH OF FRESH AIR.
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THORPE, AMELIA
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CREATIVE directors ,CORPORATE directors ,AIR filters ,PRODUCT managers ,CABINETS (Furniture) ,KITCHENS - Abstract
This article discusses different types of kitchen extraction systems and their features. It explains that wall-mounted extractors, also known as chimney cooker hoods, are a popular and affordable option. Island extractors and ceiling extractors are also mentioned as stylish alternatives. The article also highlights the benefits of built-in extractors and induction hobs with integrated extraction. It provides tips for choosing the right extractor, such as considering the airflow circulation rate and noise levels. The article includes several product examples and prices. [Extracted from the article]
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- 2024
23. UTV TURBOCHARGERS & SUPERCHARGERS.
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OFF-road racing ,SPARK plugs ,FUEL pumps ,AIR filters ,STEEL tubes - Abstract
This article discusses various turbocharger and supercharger kits available for UTVs (Utility Task Vehicles). It highlights different manufacturers and their products, including EVP Paragon P54 Turbo Pro R System, Dynojet Turbo R/Pro XP Big Turbo, EVP 2020+ X3 Paragon P43-270 Turbo System, Bikeman Performance Turbo R/Pro XP Turbo Upgrades, Force Turbos Can-Am X3 Turbo Kit, Agency Power RZR XP Turbo Upgrade, Kraftwerks Pro R Supercharger System, Kraftwerks YXZ & KRX Supercharger Kits, Force Turbos Pro R Turbo System, LaRue Performance Premium Pro R Turbo Kit, Boondocker Pro R Rage Turbo Systems, Weller Racing YXZ1000R Turbo Kits, S&S Off-Road Division KRX/KRX4 Turbo Kits, Jackson Racing Talon Turbo Kit. Each kit is described in terms of its features, horsepower boost, and price. Contact information for each manufacturer is also provided. [Extracted from the article]
- Published
- 2024
24. BEST BUYS: FAST FORDS.
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JENKINS, SAM
- Subjects
SPARK plugs ,SPORTS cars ,EXHAUST systems ,VALUE (Economics) ,AIR filters ,TURBOCHARGERS - Abstract
This article discusses four top used Ford performance cars: the Ford Focus RS500, Ford Focus ST Edition, Ford GT, and Ford Racing Puma. The Ford Focus RS500 is a hyperhatch with impressive power and performance, limited to 500 cars worldwide. The Ford Focus ST Edition is a hot hatch with chassis and design tweaks that improve its performance and capabilities. The Ford GT is a remarkable supercar with a mid-mounted V8 engine and classic design. The Ford Racing Puma is an underappreciated gem with a well-balanced chassis and unique bodywork. Each car has its own unique features and strengths, making them desirable options for performance car enthusiasts. [Extracted from the article]
- Published
- 2024
25. Rapid virus inactivation by nanoparticles-embedded photodynamic surfaces.
- Author
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Zhang, Gengxin, Zhou, Jiewen, Lv, Quanjie, Yang, Ruihao, Zhang, Yuhan, Chu, Jing, Zhang, Haoran, Han, Yijun, Sun, Kang, Yuan, Congli, and Tao, Ke
- Subjects
- *
VIRUS inactivation , *VIRAL transmission , *SURFACE contamination , *REACTIVE oxygen species , *AIR filters , *METHYLENE blue - Abstract
[Display omitted] The persistent threat of viral epidemics poses significant risks to human health, highlighting the urgent need for antiviral surfaces to mitigate viral transmission through bioaerosols and surface contamination. However, there is still a scarcity of readily accessible antiviral coatings to address this critical concern. In this study, we demonstrate that photodynamic nanoparticle-embedded surfaces can swiftly inactivate both enveloped and non-enveloped viruses. We prepared core–shell structured methylene blue (MB)-loaded SiO 2 nanoparticles with a high reactive oxygen species (ROS) yield (0.47 ± 0.02). The superior ROS production was maintained after modifying these nanoparticles onto air filter fibers, likely due to the prevention of aggregation-caused quenching effects. Three viruses, including both enveloped and non-enveloped types, were rapidly inactivated within just 12 min (>6 log units) under medium light intensity (660 nm, 30 mW/cm2). Mechanistic studies revealed that envelope glycoproteins are the primary targets for this rapid inactivation. Thus, photodynamic nanoparticle-embedded surfaces offer a straightforward and adaptable strategy in the fight against viral epidemics. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
26. Functionalized Double‐Gradient Janus Filters for Full‐Scale Capture and Inactivation of Multiscale Aqueous Bioaerosols.
- Author
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Zhou, Zhiqiang, Wang, Di, You, Tianle, Pan, Zhengyuan, Xu, Guilong, Liang, Yun, and Tang, Min
- Subjects
- *
AIR filters , *AEROSOLS , *PAPERMAKING , *WETTING , *FIBERS - Abstract
Exposure to bioaerosols can result in severe infection and even death, prompting the development of numerous air filters to capture and inactivate bioaerosols. Although the wettability of filter media determines its bioaerosol‐capture efficiency, the dynamic collision behavior of multiscale aqueous bioaerosols on most filter media is poorly understood. A double‐gradient Janus paper (Janus paper) with a pore‐size gradient, asymmetric wettability, and biocidal and bioadhesion properties is fabricated in this study using an industrially available papermaking process. The dynamic collision behavior at the micrometer and millimeter scales indicates that the Janus paper enables the full‐scale blocking and/or capture of aqueous aerosols by a two‐step mechanism where the water‐repellent top layer blocks large‐size aqueous aerosols, while the hydrophilic bottom layer permits the adherence of small‐size aerosols to its fibers. The Janus paper exhibits a higher capture and inactivation capacity (inactivation efficiency: 98.3%), better dust‐holding capacity (> 21 g m−2), and a longer lifetime than commercial filter media. Commercial air purifiers comprising the Janus paper exhibit high potential for large‐scale commercial applications owing to the facile, low‐cost, and scalable fabrication method. This study enables future research on efficient and practicable Janus‐paper filter media. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
27. Packing Incubation and Addition of Rot Fungi Extracts Improve BTEX Elimination from Air in Biotrickling Filters.
- Author
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Rybarczyk, Piotr, Cichon, Krzysztof, Kucharska, Karolina, Dobrzyniewski, Dominik, Szulczyński, Bartosz, and Gębicki, Jacek
- Subjects
- *
AIR filters , *PRESSURE drop (Fluid dynamics) , *NEW business enterprises , *ETHYLBENZENE , *XYLENE - Abstract
The removal of benzene, toluene, ethylbenzene, and xylene (BTEX) from air was investigated in two similar biotrickling filters (BTFs) packed with polyurethane (PU) foam, differing in terms of inoculation procedure (BTF A was packed with pre-incubated PU discs, and BTF B was inoculated via the continuous recirculation of a liquid inoculum). The effects of white rot fungi enzyme extract addition and system responses to variable VOC loading, liquid trickling patterns, and pH were studied. Positive effects of both packing incubation and enzyme addition on biotrickling filtration performance were identified. BFF A exhibited a shorter start-up period (approximately 20 days) and lower pressure drop (75 ± 6 mm H2O) than BTF B (30 days; 86 ± 5 mm H2O), indicating the superior effects of packing incubation over inoculum circulation during the biotrickling filter start-up. The novel approach of using white rot fungi extracts resulted in fast system recovery and enhanced process performance after the BTF acidification episode. Average BTEX elimination capacities of 28.8 ± 0.4 g/(m3 h) and 23.1 ± 0.4 g/(m3 h) were reached for BTF A and BTF B, respectively. This study presents new strategies for controlling and improving the abatement of BTEX in biotrickling filters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
28. Method of Calculating Outdoor PM 2.5 Concentration in Fresh Air Systems Based on Population Density Distribution Regions.
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Tang, Daqian, Guo, Xiaoke, Zhao, Qing, and Zhang, Xin
- Subjects
AIR filters ,POPULATION density ,MATHEMATICAL induction ,CITIES & towns ,PARTICULATE matter - Abstract
With the gradual increase in population density, population migration poses unprecedented challenges to urban environments and their capacity. The fresh air system effectively ensures fresh air in indoor environments. An important parameter affecting the selection of a fresh air filtration system is calculating particulate matter at a concentration of less than 2.5 μm (PM
2.5 ). The PM2.5 concentration values of 31 cities in China from 2017 to 2020 were selected for analysis in this study. Based on mathematical induction and population density zoning, a new method that combines population density zoning is proposed, and the recommended constant K values for different regions are analyzed. The definition of K refers to the ratio of the outdoor design concentration value of PM2.5 to the annual average at different guarantee rates. The air filters for fresh air systems in five typical cities (Harbin, Beijing, Urumqi, Xi'an, Guangzhou) are also used as examples. The K values and selection differences under different recommendation methods are compared and analyzed. Under population migration and urbanization scenarios, the results indicate that the recommended K of the seven major regions method was optimal. Under these conditions, the recommended K values for five typical cities under strict and normal conditions differ from their average K values by 0.07 and 0.04, respectively. This method can accurately select fresh air filtration systems under different population densities; however, population density is related to factors such as policies and the economy and must be updated and revised regularly. On the whole, it provides reference values for the selection of PM2.5 design concentrations in fresh air systems under population distribution differentiation. [ABSTRACT FROM AUTHOR]- Published
- 2024
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29. Efficacy improvement technique of air-filtration unit affected by biofouling using electroless Ni-Cu-P coating.
- Author
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Ghosh, Niloy, De, Jhumpa, and Chowdhury, Amit Roy
- Subjects
AIR filters ,FOULING ,CORROSION & anti-corrosives ,ULTRAVIOLET radiation ,NICKEL - Abstract
Moisture from ar is often responsible for biofouling and corrosion on the inner walls of the air filtration system and there by affecting the bacteria colony forming units (CFU Count). This phenomenon is more prevalent in humid environment. Applying electroless Nickel-Copper-Phosphorous (Ni-Cu-P) coating on mild steel helps to prevent bio fouling. An air filtration unit with inner walls coated with nano-TiO
2 and inlet filter mesh made of Luffa and coated activated charcoal and zeolite is used in the experimentation process. The inner chamber is also radiated by band C of Ultraviolet sources (UVC) with 254 nm wavelength. A sudden spike in bacteria colony count has been observed as the air filtration unit remains in off mode for prolonged duration of time. The efficacy of the air filtration unit upon remaining in off- mode for a long time has been determined in the present work considering the bacterial colony count as response. Electroless Ni-Cu-P coating has been applied at selected locations previously affected by biofouling. A predictive model has been developed following response surface methodology using bacterial colony count as response and the composition of the electroless coating bath as the process parameters. Genetic algorithm was applied for the determination of the best possible constitution of chemical coating bath for the minimization of the bacterial colony count. Bacteria Colony formation was significantly affected by the sources of Nickel ion, Copper ion and the concentration of reducing agent in the electroless Ni-Cu-P coating bath. The confirmation run showed that the observed CFU count at the optimum condition converges with the data obtained from Genetic Algorithm. [ABSTRACT FROM AUTHOR]- Published
- 2024
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- View/download PDF
30. Efficiency of Backwashing in Removing Solids from Sand Media Filters for Drip Irrigation Systems.
- Author
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Duran-Ros, Miquel, Pujol, Joan, Pujol, Toni, Cufí, Sílvia, Graciano-Uribe, Jonathan, Arbat, Gerard, Ramírez de Cartagena, Francisco, and Puig-Bargués, Jaume
- Subjects
TOTAL suspended solids ,WATER reuse ,MICROBIOLOGICAL aerosols ,SILICA sand ,IRRIGATION water ,AIR filters - Abstract
Sand media filters are especially recommended to prevent emitter clogging with loaded irrigation waters, but their performances rely on backwashing. Despite backwashing being a basic procedure needed to restore the initial filtration capacity, there is a lack of information about the solid removal efficiency along the media bed depth. An experimental filter with a 200 mm silica sand bed height was used to assess the effect of two operation velocities (30/45 and 60/75 (filtration/backwashing) m h
−1 ) and two clogging particles (inorganic sand dust and organic from a reclaimed effluent) on the efficiency of backwashing for removing the total suspended solids retained in different media bed slices. The average solid removal backwashing efficiency was greater with organic particles (78%) than with inorganic ones (64%), reaching its maximum at a 5–15 mm bed depth. A higher operation velocity increased the solid removal efficiency by 16%, using organic particles, but no significant differences were observed with inorganic particles. The removal efficiencies across the media bed were more uniform with organic particles (63–89%) than with inorganic (40–85%), which makes it not advisable to reduce the media height when reclaimed effluents are used. This study may contribute to future improvements in sand media filter design and management. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
31. Investigating the impact of a window air conditioner with H-14 HEPA filter on lessening SARS-COV-2 aerosols.
- Author
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Huzayyin, Omar, Zaki, Ahmed, and Ali, Shady
- Subjects
HEPA filters ,MICROBIOLOGICAL aerosols ,AIR purification ,INDOOR air quality ,AIR filters - Abstract
This research breaks new ground by proposing a unique solution to combat SARS-COV-2 aerosols: modifying a readily available window air conditioner's indoor blower to accommodate a HEPA (high-efficiency particulate air) filter. While traditional public health measures like lockdowns and mask-wearing remain crucial, this study explores an innovative engineering approach to air purification within homes and offices. The widespread impact of COVID-19 across various sectors—agriculture, manufacturing, finance, and more—necessitates exploring diverse solutions. Current efforts to utilize HEPA filters in HVAC systems face limitations. These filters, while highly effective at capturing airborne particles, increasingly impede airflow and require substantial pressure, posing challenges for standard HVAC systems to maintain efficient operation. This study addresses this critical gap by proposing a targeted modification to a specific window air conditioner (AC) model (GJC07AF-K3RNB9D) to incorporate an H-14 HEPA filter. Utilizing cutting-edge design tool (CF-TURBO) and advanced simulation software (STARCCM +), the research will provide a new blower specifically optimized for this application. This virtual testing will meticulously evaluate the modified system's performance, ensure optimal airflow, predict noise levels, and identify any potential design flaws before implementing the modification in a physical prototype. The success of this study could pave the way for the development of increasingly efficient and accessible HEPA-based air purification solutions for everyday use, particularly in areas with limited resources. Furthermore, this research can be a valuable foundation for future work aimed to increasingly improve indoor air quality (IAQ). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Spark Discharge Aerosol‐Generated Copper‐Based Nanoparticles: Structural & Optical Properties; Application on the Antiviral (SARS‐CoV‐2) and Antibacterial Improvement of Face Masks.
- Author
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Giannakopoulos, Konstantinos, Lasithiotakis, Michael, Karakasis, Charalampos, Gini, Maria, Gardelis, Spyros, Karakasiliotis, Ioannis, Mouti, Nafsika, Xesfyngi, Yvonni, Manolis, Georgios K., Georgoutsou‐Spyridonos, Maria, Dimitriou, Marios, and Eleftheriadis, Kostas
- Subjects
- *
MEDICAL masks , *AIR filters , *COPPER , *NANOPARTICLES , *SUBSTRATES (Materials science) - Abstract
Nanoparticle formation by Spark Discharge Aerosol Generation offers low‐cost fabrication of nanoparticles, without the use of chemicals or vacuum. It produces aerosol particles of a few nanometers in size with high purity. In this work, copper‐based ‐CuO (tenorite) and Cu‐ nanoparticles are produced, characterized and used to modify face mask air filters, achieving the introduction of antibacterial and antiviral properties. A range of characterization techniques have been employed, down to the atomic level. The majority of the particles are CuO (of a few nanometers in size that agglomerate to form aggregates), the remainder being a small number of larger Cu particles. The particles were deposited on various substrates, mainly fiber filters in order to study them and use them as biocidal agents. On face masks, their antibacterial activity against Escherichia coli (E.coli) results in a 100 % decrease in bacteria cell viability. Their antiviral activity on face masks results in a 90 % reduction of the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS‐CoV‐2) viability, 15 minutes post the application of the virus stock solution. This highlights the effectiveness of this approach, its simplicity, its low cost and its excellent environmental credentials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
33. Assessment and design of filters and masks against COVID-19 via modeling and simulations.
- Author
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Zhang, Lydia, Alshaikh, Mohamed K., and Lekakou, Constantina
- Subjects
- *
MATERIALS testing , *AIR filters , *PRODUCT design , *N95 respirators , *SIMULATION methods in education , *COMMERCIAL product evaluation , *PERMEABILITY , *MEDICAL masks , *PARTICULATE matter , *COVID-19 , *INDUSTRIAL hygiene , *INDUSTRIAL safety - Abstract
This study aimed to evaluate and design masks against viruses, especially SARS-CoV-2 associated with COVID-19. A continuum filtration model was developed where the rate of particle deposition and "sticking" on the filter fibers is a critical term in the mass transfer, together with permeation velocity, filter porosity, tortuosity, and Brownian diffusion. CFD simulations of the airflow during respiration lead to the recommendation that the filter permeability should be above 4 × 10−11 m2 to direct the airflow for effectiveness against virus particles; otherwise, low filter permeabilities cause the unfiltered air to flow preferentially through the leak gaps between the mask and the headform. Different mask filters with microstructural and geometry data from the literature are assessed via filtration simulations for breathability and filtration efficiency. The results demonstrate that a surgical mask of 25% porosity, pore size of 150 µm and permeability of 4.4 × 10−11 m2 can achieve 100% minimum efficiency while demonstrating high breathability, complying with the criteria of FFP3, N95, and surgical Class II and IIR masks. Selected cotton and synthetic cloths as well as electrospun fiber layers are predicted to comply with FFP2, N95, and surgical mask Class II and IIR standards. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Evaluation of PVC and PTFE filters for direct-on-filter crystalline silica quantification by FTIR.
- Author
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Osho, Bankole, Elahifard, Mohammadreza, Wang, Xiaoliang, Abbasi, Behrooz, Chow, Judith C., Watson, John G., Arnott, W. Patrick, Reed, Wm. Randolph, and Parks, David
- Subjects
- *
ENVIRONMENTAL monitoring equipment , *SILICA analysis , *AIR pollution , *DUST , *RESEARCH funding , *AIR filters , *FILTERS & filtration , *INHALATION injuries , *PARTICLES , *DESCRIPTIVE statistics , *INFRARED spectroscopy , *VINYL chloride , *POLYTEF , *OCCUPATIONAL exposure , *SENSITIVITY & specificity (Statistics) - Abstract
Direct-on-Filter (DoF) analysis of respirable crystalline silica (RCS) by Fourier Transform Infrared (FTIR) spectroscopy is a useful tool for assessing exposure risks. With the RCS exposure limits becoming lower, it is important to characterize and reduce measurement uncertainties. This study systematically evaluated two filter types (i.e., polyvinyl chloride [PVC] and polytetrafluoroethylene [PTFE]) for RCS measurements by DoF FTIR spectroscopy, including the filter-to-filter and day-to-day variability of blank filter FTIR reference spectra, particle deposition patterns, filtration efficiencies, and pressure drops. For PVC filters sampled at a flow rate of 2.5 L/min for 8 h, the RCS limit of detection (LOD) was 7.4 μg/m3 when a designated laboratory reference filter was used to correct the absorption by the filter media. When the spectrum of the pre-sample filter (blank filter before dust sampling) was used for correction, the LOD could be up to 5.9 μg/m3. The PVC absorption increased linearly with reference filter mass, providing a means to correct the absorption differences between the pre-sample and reference filters. For PTFE, the LODs were 12 and 1.2 μg/m3 when a designated laboratory blank or the pre-sample filter spectrum was used for blank correction, respectively, indicating that using the pre-sample blank spectrum will reduce RCS quantification uncertainty. Both filter types exhibited a consistent radially symmetric deposition pattern when particles were collected using 3-piece cassettes, indicating that RCS can be quantified from a single measurement at the filter center. The most penetrating aerodynamic diameters were around 0.1 µm with filtration efficiencies ≥ 98.8% across the measured particle size range with low-pressure drops (0.2–0.3 kPa) at a flow rate of 2.5 L/min. This study concludes that either the PVC or the PTFE filters are suitable for RCS analysis by DoF FTIR, but proper methods are needed to account for the variability of blank absorption among different filters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
35. Effectiveness of Air Filtration in Reducing PM 2.5 Exposures at a School in a Community Heavily Impacted by Air Pollution.
- Author
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Thompson, McKenna, Castorina, Rosemary, Chen, Wenhao, Moore, David, Peerless, Kyle, and Hurley, Susan
- Subjects
- *
INDOOR air quality , *PARTICULATE matter , *AIR quality , *AIR warfare , *AIR filters , *AIR pollution - Abstract
Reducing children's exposure to air pollution is a priority among California communities heavily impacted by air pollution exposures. We conducted an observational air quality study at a school to investigate the effectiveness of improved Heating, Ventilation, and Cooling (HVAC) system filters and portable air cleaners (PACs) in reducing children's exposure to fine particulate matter (PM2.5) under real-world classroom conditions. This study included five classrooms, three of which had PACs. Halfway through the study period, high-efficiency HVAC filters were installed in all five classrooms. Continuous measurements of outdoor and in-classroom PM2.5 concentrations were used to evaluate filtration effectiveness. The air filtration strategies, alone and in combination, demonstrated 14–56% reductions in indoor PM2.5 concentrations compared to outdoor levels. There were significant improvements in filtration resulting from HVAC filter upgrades in the two classrooms without PACs (11% and 22% improvement, p < 0.001). Upgrading HVAC filters in classrooms with PACs did not significantly improve filtration effectiveness, suggesting that utilizing both strategies simultaneously may not meaningfully improve air quality under these circumstances. CO2 data, as a proxy for ventilation, helped demonstrate that the observed filtration effectiveness was likely impacted by the variable HVAC system use and open doors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. One‐Dimensional View of the Structural Changes in the Filtering Layer during Continuous Dust Deposition – A New Approach to a Holistic View of the Filtration Process.
- Author
-
Zhang, Qian
- Subjects
- *
AIR filters , *DUST , *CONTINUOUS processing - Abstract
The overall filtration process is viewed from a new perspective: There is a continuous, systematic change in the structure of the active deposition zone of a given filter layer, here as the so‐called active filtering layer. During the overall filtration process, the filtering layer is transformed from the initial clean filter medium, via continuous particle deposition under the given filtration conditions, to a new, dynamically preserved stable porous structure, i.e. the active deposition zone on the upstream side of the dust cake. Based on 3D simulations of cake formation on model filters for fabric filters, 1D deposition profiles during the continuous filtration process are evaluated and converted into a dimensionless form, to describe the structural changes in the filtering layer. The stable 1D deposition profile during the phase of surface filtration can be well described with a logistic function. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Effect of air humidity on the pulse-jet cleaning performance of cartridge filter for collecting hygroscopic adhesive dusts.
- Author
-
Zhang, Mingxing, Li, Yang, Yan, Cuiping, Huang, Wanlan, Peng, Yuyan, and Wang, Yunduan
- Subjects
- *
HUMIDITY , *DUST removal , *COMPRESSED air , *DUST , *WIND speed , *AIR filters , *ADHESIVES - Abstract
Pulse-jet cartridge filters are widely used in industrial dust removal. However, the accumulation of highly sticky dust can cause irreversible blockage of cartridges. This is primarily due to the humidity of the air on the cleaning performance of the filter cartridge. Therefore, this article proposed a new method to solve it by changing the injection air source (nitrogen, compressed air after suction dryer treatment and compressed air after cold dryer treatment), the influence of humidity on system strength and dust residues was assessed. We define absolute humidity above 10 g m−3 as a high humidity condition and vice versa as a low humidity condition. The conclusions are that the injection effect only considers the water content of the injection air source: nitrogen > compressed air after suction dryer treatment > compressed air after cold dryer treatment. In low humidity conditions, the injection air source is the main influence factor, plus the water content of the injection air source, the greater the resistance of the system and the dust residues. In high humidity conditions, the humidity of the air is the most important influence. When the gas-solid concentration and filtration wind speed are constant, the system strength and dust residues increase with the increase in humidity. This study provides new ideas and reliable data sources for the industrial collection of adhesive dust. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Exploring the Integration of a Novel Photocatalytic Air Purification Façade Component in Buildings.
- Author
-
Lopez-Besora, Judit, Pardal, Cristina, Isalgue, Antonio, and Roig, Oriol
- Subjects
NATURAL ventilation ,AIR purification ,INDOOR air quality ,BUILDING envelopes ,AIR filters - Abstract
Indoor air quality determines the comfort, health, and wellbeing of people in buildings. Windows are the optimal elements for providing natural ventilation and fresh air, but the outside contains suspended particles that can be harmful in high concentrations. This work presents an openable and double-glazed façade component with a cavity that includes a series of slats that filter the air and depurate it by means of a photocatalytic reaction (TiO
2 ). This component integrates the functions of ventilation, solar protection, and air purification, which were analysed in the slat and the façade component to approve a preliminary design. To this end, it was applied to a specific case, a non-residential building at a latitude 41° N in a Mediterranean climate. The results show the optimal dimensions according to solar radiation and ventilation in this specific case and the method used to obtain them, along with the increase in the temperature of the incoming air with respect to the outside (10 °C). Finally, the results obtained from a photocatalytic coating sample show that the NOx degradation can be up to 9%. All these results confirm the applicability of this component in buildings and pave the way for further research. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
39. Study of photocatalytic inactivation of airborne microorganisms on various functionalized filter media: comparative analysis.
- Author
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Flores, Marina, Passalía, Claudio, Labas, Marisol Daniela, and Brandi, Rodolfo Juan
- Published
- 2024
- Full Text
- View/download PDF
40. 基于表面辐射声信号的柴油机 进气及齿轮故障诊断.
- Author
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李斌, 林杰威, 朱小龙, 林耕毅, 张益铭, and 张俊红
- Subjects
FAULT diagnosis ,ACOUSTIC vibrations ,SUPPORT vector machines ,AIR filters ,SEARCH algorithms ,ANECHOIC chambers - Abstract
Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
41. Heat‐Resistant Air Filters Based on Self‐Sustained Electrostatic and Antibacterial Polyimide/Silver Fiber Mats.
- Author
-
Lyu, Pei, Ju, Zheng, Hu, Jun, Pan, Heng, Li, Xing, Liu, Yuemei, Ren, Jie, Shang, Bin, Liu, Xin, and Xu, Weilin
- Subjects
- *
AIR filters , *ESCHERICHIA coli , *SILVER , *FIBERS , *AIR pollution , *HEAT resistant alloys - Abstract
Air pollution containing microorganisms poses a major hazard to human health. It is critical to develop air filters that are both highly efficient for indoor use and suitable for use in industrial settings. Developing long‐lasting electrostatic force‐assisted filtration while keeping high‐temperature resistance and antibacterial qualities is still challenging. Here, centrifugal spinning is used to fabricate fiber mats consisting of polyimide with silver incorporation (PI/Ag). The electrostatic force remained over –700 V after 330 days. The strong electrostatic effect improves the filtration efficiency, resulting in a high PM0.3 removal efficiency of 99.1% with a low‐pressure drop of 103.67 Pa. The high filtration efficiency remains above 91.3% for PM0.3 after placing it for 330 days and heating it at 280 °C. The PI/Ag fiber mats also show antimicrobial properties against the E. coli (Gram‐negative) and S. aureus (Gram‐positive) with prominent bacteriostatic zones >1.2 mm. The PI/Ag fiber mat filters are expected to have great potential for multi‐scenario air filtration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Non-thermal plasma for decontamination of bacteria trapped in particulate matter filters: plasma source characteristics and antibacterial potential.
- Author
-
Helmke, Andreas, Curril, Ingrid, Mrotzek, Julia, Schulz, Jannik, and Viöl, Wolfgang
- Subjects
- *
NON-thermal plasmas , *PARTICULATE matter , *PLASMA sources , *ESCHERICHIA coli , *ELECTRIC power , *MICROBIOLOGICAL aerosols , *AIR filters , *THERMAL plasmas - Abstract
The aims of this study encompass the characterization of process parameters and the antimicrobial potential during operation of a novel non-thermal plasma (NTP) source in a duct system containing a particulate matter (PM) filter thus mimicking the interior of an air purifier. Simulating conditions of a long-term operation scenario, in which bacterial aerosols in indoor environments accumulate on PM filters, the filter surfaces were artificially inoculated with Escherichia coli (E. coli) and exposed to an air stream enriched with reactive species. Electrical power consumption, key plasma parameters, volume flow and air flow velocity, reactive gas species concentrations as well as inactivation rates of E. coli were assessed. The NTP operated at a gas temperature close to ambient air temperature and featured a mean electron energy of 9.4 eV and an electron density of 1∙1019 m−3. Ozone was found to be the dominating reactive gas species with concentrations of approx. 10 ppm in close vicinity to the PM filters. An inactivation rate of 99.96 % could be observed after exposure of the PM filters to the gas stream for 15 min. This inactivation efficiency appears very competitive in combating realistic bacterial aerosol concentrations in indoor environments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. FFP快开卧式压滤机在锂云母精矿脱水系统中的应用.
- Author
-
郭伟, 陈一锋, 谢添, and 唐立靖
- Subjects
- *
PARTICULATE matter , *POLYMER aggregates , *POLYALUMINUM chloride , *PLANT drying , *MINERAL processing , *AIR filters - Abstract
Lemica concentrate in Yichun area of Jiangxi province is widely used belt filter for dehydration, belt filter not only covers a large area of equipment, but also low dehydration efficiency, filtered lemica concentrate high water, generally greater than 18%, lemica concentrate high water directly leads to transportation costs and downstream lithium carbonate plant drying costs high. In order to solve this problem, a concentrator in Yichun area used FFP horizontal fast-opening filter press produced by a certain manufacturer to dehydrate leucite concentrate. The effects of FFP horizontal fast-opening filter press filter cloth type, cycle time, working pressure, filter aid type and dosage of leucite concentrate on the water content of leucite concentrate were investigated. The test results show that when the FFP horizontal fast opening filter press uses nylon monofilm filter cloth with air permeability of 300L/㎡/min, cycle time of 930s, working pressure of 11.0bar, and the filter aid uses polyaluminum chloride 450g/t, the water content of lemica concentrate is 13.80%, which is obviously lower than that of other concentrator in Yicchun area. Filter aid polyaluminum chloride is conducive to reducing water, this is because the molecular chain of polyaluminum chloride is fixed on the surface of different fine particles or very fine particles, and the bridge between the fine particles or very fine particles forms a polymer aggregate, and the aggregate will not cause the filter hole blockage of the filter cloth during the filtration process. Compared with the belt filter, the FFP horizontal fast-opening filter used by a concentrator in Yichun area has the characteristics of small equipment area, high dehydration efficiency and high degree of automation, which solves the industry problem of high water content of leucite concentrate in Yichun area. It is the first large-scale successful application in the leucite mineral processing industry, and has a very important demonstration significance in the industry. The future application prospect is broad. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Experimental Dust Absorption Study in Automotive Engine Inlet Air Filter Materials.
- Author
-
Dziubak, Tadeusz
- Subjects
- *
AIR filters , *DUST , *INTERNAL combustion engines , *MATERIALS testing , *ABSORPTION coefficients , *AIR quality - Abstract
The purpose of this study was to empirically evaluate the performance of fibrous materials that meet the criteria for inlet air filtration in internal combustion engines. The characteristics of filtration efficiency and accuracy, as well as the characteristics of flow resistance, were determined based on the mass of dust accumulated in the filter bed during the filtration process. Single-layer filter materials tested included cellulose, polyester, and glass microfiber. Multilayer filter media such as cellulose–polyester–nanofibers and cellulose–polyester were also examined. A new composite filter bed—consisting of polyester, glass microfiber, and cellulose—and its filtration characteristics were evaluated. Utilizing specific air filtration quality factors, it was demonstrated that the composite is characterized by high pre-filtration efficiency (99.98%), a short pre-filtration period (qs = 4.21%), high accuracy (dpmax = 1.5–3 µm) for the entire lifespan of the filter, and a 60–250% higher dust absorption coefficient compared to the other tested materials. A filtration composite bed constructed from a group of materials with different filtration parameters can be, due to its high filtration efficiency, accuracy, and dust absorption, an excellent filter material for engine intake air. The composite's filtration parameters will depend on the type of filter layers and their order relative to the aerosol flow. This paper presents a methodology for the selection and testing of various filter materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Temporal trends in indoor bioaerosols: implications for dental healthcare environments.
- Author
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Akhtar, Naseem, Tahir, Arifa, Abbas, Moneeza, Zaman, Nasib, Qadir, Abdul, and Arshad, Muhammad
- Subjects
- *
MICROBIOLOGICAL aerosols , *INDOOR air quality , *AIR filters , *DRUG resistance in bacteria , *MICROBIAL contamination , *AIR sampling , *MEDICAL care - Abstract
Antibiotic resistance, a significant public health hazard, is predicted to cause 10 million deaths worldwide by 2050. The study aimed to identify culturable bioaerosols in the indoor air of dental units in Lahore and assess their antibiotic resistance. Air samples were collected from 10 dental unit locations at different distances, with average concentrations of fungi and bacteria falling within intermediate ranges, per the Global Index of Microbial Contamination (GIMC/m3) index. The study found higher antibiotic-resistant strains in hospital dental units, particularly during winter. The most vigorous strain,
S.aureus -NAJIH18, exhibited 70% resistance to ceftazidime. The research highlights the importance of quantifying microbial pollutants for evaluating their source and complexity. It suggests proactive mitigation techniques, such as focused cleaning and air filtration, to improve indoor air quality can mitigate the spread of antibiotic-resistant strains. These insights offer hope in combating the growing public health threat of antibiotic resistance. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
46. Electrospinning and Partial Etching Behaviors of Core–Shell Nanofibers Directly Electrospun on Mesh Substrates for Application in a Cover-Free Compact Air Filter.
- Author
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Lee, Yujung, Jung, Seungwoo, and Yun, Ji Sun
- Subjects
- *
METHOXYPROPANOL , *AIR filters , *NANOFIBERS , *INDOOR air quality , *ELECTROSPINNING , *ETCHING - Abstract
The exposure of workers to propylene glycol monomethyl ether acetate (PGMEA) in manufacturing environments can result in potential health risks. Therefore, systems for PGMEA removal are required for indoor air quality control. In this study, core–shell zeolite socony mobil-5 (ZSM-5)/polyvinylpyrrolidone–polyvinylidene fluoride nanofibers were directly electrospun and partially wet-etched on a mesh substrate to develop a cover-free compact PGMEA air filter. The electrospinning behaviors of the core–shell nanofibers were investigated to optimize the electrospinning time and humidity and to enable the manufacture of thin and light air-filter layers. The partial wet etching of the nanofibers was undertaken using different etching solvents and times to ensure the exposure of the active sites of ZSM-5. The performances of the ZSM-5/PVDF nanofiber air filters were assessed by measuring five consecutive PGMEA adsorption–desorption cycles at different desorption temperatures. The synthesized material remained stable upon repeated adsorption–desorption cycles and could be regenerated at a low desorption temperature (80 °C), demonstrating a consistent adsorption performance upon prolonged adsorption–desorption cycling and low energy consumption during regeneration. The results of this study provide new insights into the design of industrial air filters using functional ceramic/polymer nanofibers and the application of these filters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. After the Smoke Clears: Wildland-Urban Interface Fires and Residues in Nearby Homes.
- Author
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Averett, Nancy
- Subjects
- *
INDOOR air pollution prevention , *POLYCYCLIC aromatic hydrocarbon analysis , *ORGANIC compound analysis , *METAL analysis , *ENVIRONMENTAL monitoring equipment , *AIR pollution , *ENVIRONMENTAL health , *ARCHITECTURE , *WILDFIRES , *HEALTH status indicators , *DUST , *DIFFUSION of innovations , *AIR filters , *PRODUCT design , *HOME environment , *SIMULATION methods in education , *METROPOLITAN areas , *AWARDS , *RESEARCH , *SMOKE , *INDOOR air pollution , *PARTICULATE matter , *PUBLIC health - Abstract
The article discusses the results of a study on the impacts of wildfire smoke on health and indoor air quality. Topics mentioned include the analysis of dust for the presence of metals, metalloids, and polycyclic aromatic hydrocarbons, the levels of volatile organic compounds in affected and unaffected homes, and a description of modeling homes and materials experiment to simulate indoor air quality.
- Published
- 2024
- Full Text
- View/download PDF
48. Standardization of microwave-assisted extraction procedures for characterizing non-labile metallic nanoparticles in environmental solid samples by means of single particle ICP-MS.
- Author
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Gómez-Pertusa, Carlos, García-Poyo, M. Carmen, Grindlay, Guillermo, Pedraza, Ricardo, Yañez, M. Adela, and Gras, Luis
- Subjects
- *
ENVIRONMENTAL sampling , *SCIENTIFIC apparatus & instruments , *MICROWAVE ovens , *AIR filters , *NANOPARTICLES , *PARTICLE analysis - Abstract
Microwave-assisted extraction (MAE) treatments seem to be a promising sample preparation strategy to isolate nanomaterials (NMs) from environmental samples prior to single particle inductively coupled plasma mass (spICP-MS) determination. Nevertheless, because previous studies make use of domestic microwave ovens (DMOs), several shortcomings arise that compromise the analysis such as lack of control of experimental variables, limited operating conditions, and uncontrolled sample heating leading to irreproducibility issues. The goal of this work is to adapt previously developed MAE treatments for soil and air filters with the DMO apparatus to state-of-the-art scientific microwave ovens (SMOs) in order to standardize current analytical protocols for NM characterization. Results show that, by working with an SMO, non-labile metallic NMs (Pt-AuNPs) are quantitively extracted from soil and air filter samples unaltered in 10 min and 6 min, respectively, at 1200 W by using 10 mL of NaOH 0.1 M solution. The use of a SMO system allows improving accuracy (above 10% of the particle recovery), precision (above 5% of the RSD) and sample throughput (above 4-fold) when compared to the DMO ones. According to these findings, MAE seems to be a powerful strategy for routine analysis of non-labile NMs in environmental samples. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Wavelength calibration using MEMS-enabled double filter configuration for air gap sensing in the tunable Fabry–Pérot filter.
- Author
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Sahani, Pratyasha, Nabana, Shiori, Okatani, Taiyu, Inomata, Naoki, and Kanamori, Yoshiaki
- Subjects
- *
MICROELECTROMECHANICAL systems , *AIR filters , *CALIBRATION , *WAVELENGTHS , *AIR gap (Engineering) - Abstract
We fabricate a microelectromechanical systems (MEMS)-based device configuring the tunable air gap Fabry–Pérot filter (FPF) with a static gradient thickness filter on the same platform. The proposed double filter configuration offers a wavelength calibration approach that accurately estimates the air gap dimension in the tunable air gap FPF. The wavelength calibration is performed by utilizing the spectrally-selective and spatially-resolved transmission characteristics of the tunable air gap FPF and the static gradient thickness filter, respectively. The MEMS-compatible chip-level integration of the static gradient thickness filter facilitates device miniaturization to enable its use in handheld devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Approaches to Recycling of Engine Air Filters.
- Author
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Wilke, Christian, Kaas, Alexandra, and Peuker, Urs
- Subjects
- *
ENGINES , *COMPOSITE materials , *AIR filters , *SIZE reduction of materials , *POLYPROPYLENE - Abstract
It is becoming increasingly important to be able to recycle mass‐produced products such as engine air filters. Different processes were tested to investigate whether it is possible to recycle the composite material. Thereby, comminution with cutting stress is particularly suitable for disintegration. Next on, the filter medium could be separated very well with the help of a zig‐zag separator. The sorting of polyurethan foam and polypropylene hard plastic could be achieved with a dense media separation. It became clear that the pretreatment, which is intended to liberate the material, has a significant influence on the sorting result and the purity of the products. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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