Air Transmission Research Articles

A new system to prevent SARS-CoV-2 and microorganism air transmission through the air circulation system of endoscopes.

Background and study aims Evidence for the modes of transmission of SARS-CoV-2 remains controversial. Recently, the potential for airborne spread of SARS-CoV-2 has been stressed. Air circulation in gastrointestinal light source boxes and endoscopes could be implicated in airborne transmission of microorganisms. Methods The ENDOBOX SC is a 600 × 600 mm cube designed to contain any type of machine used during gastrointestinal endoscopy. It allows for a 100-mm space between a machine and the walls of the ENDOBOX SC. To use the ENDOBOX SC, it is connected to the medical air system and it provides positive flow from the box to the endoscopy room. The ENDOBOX SC uses medical air to inflate the digestive tract and to decrease the temperature induced by the microprocessors or by the lamp. ENDOBOX SC has been investigated in different environments. Results An endoscopic procedure performed without ventilation was interrupted after 40 minutes to prevent computer damage. During the first 30 minutes, the temperature increased from 18 °C to 31 °C with a LED system. The procedure with fans identified variations in temperature inside the ENDOBOX SC from 21 to 26 °C (± 5 °C) 1 hour after the start of the procedure. The temperature was stable for the next 3 hours. Conclusions ENDOBOX SC prevents the increase in temperature induced by lamps and processors, allows access to all necessary connections into the endoscopic columns, and creates a sterile and positive pressure volume, which prevents potential contamination from microorganisms.

Inactivation of airborne SARS-CoV-2 by thyme volatile oil vapor phase

BackgroundThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic mainly through air transmission. Novel variants are emerging and thus innovative methods of air disinfection still warrant exploration. Essential oils with virucidal properties may be an alternative to known air disinfectants. ObjectivesAnalysis of virucidal potential of thyme oil vapor phase against airborne SARS-CoV-2. Materials and methodsChemical composition of thyme oil was analyzed by Gas chromatography–mass spectrometry.Thyme oil was tested in solution in different dilutions against soluble SARS-CoV-2. For air disinfection analysis, different volumes of thyme oil were placed in a container with hot water and its vapor phase was tested against airborne/aerosolized SARS-CoV-2 in a 30 m3 room. The aerosolized virus was collected in a gelatine filter using a vacuum system after the test and the collected virus was quantified utilizing inoculations of serial dilutions into 96-well plates with VERO E6 cells. ResultsThe main component of thyme oil was carvacrol. Thyme oil had virucidal action both in solution and in the air. Thyme oil at 1/1000 dilution (volume/volume, final concentration) in a solution eliminated more than 99,99% of SARS-CoV-2 in the solution in 60 min. In air disinfection tests in 30 m3 room, vapor phase of 40 ml of extracted thyme oil eliminated more than 99,99% (>4 LOG10) of airborne SARS-CoV-2, and vapor phase of 20 ml of thyme oil resulted in elimination of 90,88% (1,04 LOG10) airborne SARS-CoV-2 in 60 min. ConclusionWe have shown that vapor phase of thyme oil inactivates more than 99,99% of airborne SARS-CoV-2 in a room for the first time to the best of our knowledge. This finding may have implications on the use of thyme oil as a potential air disinfectant against SARS-CoV-2.

Electrospun Nanofibrous Membranes: A Versatile Medium for Waterproof and Breathable Application.

Waterproof and breathable membranes that prevent liquid water penetration, while allowing air and moisture transmission, have attracted significant attention for various applications. Electrospun nanofiber materials with adjustable pore structures, easily tunable wettability, and good pore connectivity, have shown significant potential for constructing waterproof and breathable membranes. Herein, a systematic overview of the recent progress in the design, fabrication, and application of waterproof and breathable nanofibrous membranes is provided. The various strategies for fabricating the membranes mainly including one-step electrospinning and post-treatment of nanofibers are given as a starting point for the discussion. The different design concepts and structural characteristics of each type of waterproof and breathable membrane are comprehensively analyzed. Then, some representative applications of the membranes are highlighted, involving personal protection, desalination, medical dressing, and electronics. Finally, the challenges and future perspectives associated with waterproof and breathable nanofibrous membranes are presented.

Nanocatalysts induced self-triggering leather skin for human–machine interaction

Electronic skins mimicking the comprehensive functions of human skin are highly interesting for the development of human–machine interactions (HMI). Conventional conductive leathers face challenges of the non-uniform dispersion of conductive components and the complicated fabrication processes, hindering their applications for electronic skins. Herein, a novel ionically conductive leather skin is developed by in-situ self-triggering gelation of ionogel in the hierarchical structure of leather matrix. The core–shell structured liquid metal@catechin nanocatalysts enable rapid and uniform gelation within tens of seconds under ambient conditions. Resulting interpenetrating ionogel networks within leather matrix not only provide 3D continuous and highly conductive pathways for ionic transport, but also form multiple bonding for strong interfacial interactions. These advantageous properties endow leather skin with excellent mechanical robustness (tensile stress:17.8 MPa; toughness: 1590 kJ/m3), high air transmission rate (720 mL/cm2/h) and water vapor transmission rate (70 g/m2/h), as well as broad environmental tolerance (-80 ∼ 100 °C). Impressively, the leather skin-based sensors exhibit stable and fast response with only 40 ms. The attractive performances of leather skin are further demonstrated by a bionic glove as a gesture-discernible wearable controller for HMI. This work opens up a new horizon for developing the ionically conductive leather skin, which will have profound implications for wearable electronic systems.

Impact of Different Air Pollutants (PM10, PM2.5, NO2, and Bacterial Aerosols) on COVID-19 Cases in Gliwice, Southern Poland.

Many studies have shown that air pollution may be closely associated with increased morbidity and mortality due to COVID-19. It has been observed that exposure to air pollution leads to reduced immune response, thereby facilitating viral penetration and replication. In our study, we combined information on confirmed COVID-19 daily new cases (DNCs) in one of the most polluted regions in the European Union (EU) with air-quality monitoring data, including meteorological parameters (temperature, relative humidity, atmospheric pressure, wind speed, and direction) and concentrations of particulate matter (PM10 and PM2.5), sulfur dioxide (SO2), nitrogen oxides (NO and NO2), ozone (O3), and carbon monoxide (CO). Additionally, the relationship between bacterial aerosol (BA) concentration and COVID-19 spread was analyzed. We confirmed a significant positive correlation (p < 0.05) between NO2 concentrations and numbers of confirmed DNCs and observed positive correlations (p < 0.05) between BA concentrations and DNCs, which may point to coronavirus air transmission by surface deposits on bioaerosol particles. In addition, wind direction information was used to show that the highest numbers of DNCs were associated with the dominant wind directions in the region (southern and southwestern parts).

Pemeliharaan Lightning Arrester (LA) pada Gardu Induk Saketi 150kv di PT. PLN (Persero) ULTG Rangkasbitung

Air transmission lines are very susceptible to lightning strikes resulting in traveling waves that can enter electrical equipment. Surge propagation can cause damage to existing electrical equipment on the transmission line of the substation. One component that has an important role in the substation is the Lightning Arrester (LA) as a protection system from lightning strikes. The purpose of this research is to determine the performance of lightning arresters that are more than 10 years old. Therefore, to ensure the safety of the electric power system from surge voltages and keep the lightning arrester performance reliable, it is necessary to carry out maintenance activities on the lightning arrester. The maintenance carried out is testing Leakage Current Measurement (LCM) and replacing lightning arresters. The research method used is the observation research method in the industrial field with interviews, data collection and analysis and literature study. The results of the LCM test on the old R phase lightning arrester are 112.7 A with a percentage of 86.69% in monitor conditions. So it is necessary to replace the old lightning arresters with new conditions. As for the results of the LCM test on the replacement R phase lightning arrester (new) of 33.4 A with a percentage of 25.69% in good condition.

SARS-CoV-2 and the role of airborne transmission: a systematic review

Background: Airborne transmission is the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air. We carried out a systematic review to identify, appraise and summarise the evidence from studies of the role of airborne transmission of SARS-CoV-2. Methods: We searched LitCovid, MedRxiv, Google Scholar and the WHO Covid-19 database from 1 February 2020 to 30 May 2022 and included studies on airborne transmission. Data were dual extracted, and we assessed quality using a modified QUADAS 2 risk of bias tool. Results: We included 128 primary studies and 29 reviews on airborne SARS-CoV-2. Of the 128 primary studies, 105 (82%) reported data on RT-PCR from air samples, 28 (22%) report cycle threshold values and 36 (28%) copies per sample volume. All primary studies were observational. The research often lacked standard methods, standard sampling sizes and reporting items. We found 69 descriptions of different air samplers deployed. Of the 80 in-hospital studies that reported binary RT-PCR tests, 362/3079 air samples from 75 studies conducted in hospital ward environments were positive (median 8%, IQR=0 to 23%); 23 studies reported 74/703 RT-PCR positive air samples in the ICU setting (median 17%, IQR=0% to 38%) Thirty-eight studies reported potential air transmission in the outdoors or in the community. Twenty-six studies attempted viral culture, none of which definitively demonstrated that replication-competent SARS-CoV-2 could be recovered in the air. Conclusion: SARS-CoV-2 RNA is detectable intermittently in the air in various settings. Standardized guidelines for conducting and reporting research on airborne transmission are needed. The lack of recoverable viral culture of SARS-CoV-2 from air samples prevents firm conclusions about the definitive role of airborne transmission in SARS-CoV-2.

Effect of health education on the level of knowledge and attitude of mothers about COVID-19 prevention at posyandu of mpunda public health center of Bima City

Background of Study: Transmission of COVID-19 is made through close contact and saliva splashes/droplets, instead of air transmission. Baby is one of the most vulnerable subjects to any kind of disease due to their body's immune is still likely weak or imperfect. Providing insights on the importance of maintaining health and the danger of COVID-19 virus is necessary to conduct through some informal educational platforms to the society. Method: the research method used in the present study was quasi-experiment with pre-test and post-test with a control group design. The sampling technique used was random sampling. In this study, a bivariate test was conducted to find out the effect and difference in the level of knowledge and attitude of both the control group and experimental group. The present study, further, used the statistical test of Mann Witney and Wilcoxon Signed Rank Test.

Study of Current Instability Testing in Andongan In 150 Kva High Voltage Air Line

Air transmission lines generally use ACSR type conductors. As the demand for electrical energy increases, the effort to increase the capacity of the transmission line is carried out by optimizing the current-carrying capacity of the existing transmission line, but the problem that arises in this optimization is the increase in the voltage and slope of the conductor. This study aims to determine the effect of line current instability on conductor temperature, conductor slope, slope angle and conductor voltage, which is then useful for the construction of transmission line construction structures in accordance with the mechanical properties of the conductors used. This study uses the calculation of the heat balance equation. to calculate the conductor temperature. The Basic Span Length method is used to determine the equivalent span length

Study of Current Instability Testing in Andongan In 150 Kva High Voltage Air Line

Air transmission lines generally use ACSR type conductors. As the demand for electrical energy increases, the effort to increase the capacity of the transmission line is carried out by optimizing the current-carrying capacity of the existing transmission line, but the problem that arises in this optimization is the increase in the voltage and slope of the conductor. This study aims to determine the effect of line current instability on conductor temperature, conductor slope, slope angle and conductor voltage, which is then useful for the construction of transmission line construction structures in accordance with the mechanical properties of the conductors used. This study uses the calculation of the heat balance equation. to calculate the conductor temperature. The Basic Span Length method is used to determine the equivalent span length

An analysis of three XCT-based methods to determine the intrinsic permeability of soil aggregates

• Consistent permeability found in orthogonal flow directions by fluid flow simulation. • Skeletonization was a reliable and quick approach to parametrize Kozeny-Carman. • Pore network modelling was more sensitive to thin ramifications of the pore system. • Faster calibrated XCT-based methods can be used in large datasets for permeability. Nowadays there are many papers dealing with the analysis of the soil porous system through X-ray computed tomography (XCT). However, a reduced number of studies focus on modeling the intrinsic permeability (k) of complex porous media, such as soil, based on three-dimensional (3D) high-resolution images. The determination of k is fundamental to understanding several processes taking place in soil such as water and air transmission. Thus, this paper compares three XCT-based methods for estimating the k of the pore system of soil aggregates: i) Finite volume-based simulation (APES - Absolute Permeability Experiment Simulation), ii) Image-based parametrization of the Kozeny-Carman (IBP-KC) equation, and iii) Pore network model (PNM). The 3D image considered in the comparison of methods was acquired at the X-ray microtomography beamline at the Brazilian Synchrotron Light Facility, with a voxel size of 1.64 μm. APES was considered as a reference method for being less dependent on the configuration of sensitivity parameters. APES and PNM demonstrated to be more time consuming than the IBP-KC, the first taking longer among all for the k computation. PNM presented the drawback of higher sensitivity to thin pore ramifications, resulting in unrealistic values of k and requiring disconnecting one thinner pore to yield permeabilities comparable to the ones obtained by APES. This study demonstrated that a fine alternative to compute k for large image datasets is to calibrate faster methods (e.g., IBP-KC and PNM) against a slower but more reliable reference method (e.g., APES), using at least one 3D image, before applying the faster methods on the remaining images of the dataset.

From the nose to the lungs: the intricate journey of airborne pathogens amid commensal bacteria.

The recent COVID-19 pandemic has dramatically brought the pitfalls of airborne pathogens to the attention of the scientific community. Not only viruses but also bacteria and fungi may exploit air transmission to colonize and infect potential hosts and be the cause of significant morbidity and mortality in susceptible populations. The efforts to decipher the mechanisms of pathogenicity of airborne microbes have brought to light the delicate equilibrium that governs the homeostasis of mucosal membranes. The microorganisms already thriving in the permissive environment of the respiratory tract represent a critical component of this equilibrium and a potent barrier to infection by means of direct competition with airborne pathogens or indirectly via modulation of the immune response. Moving down the respiratory tract, physicochemical and biological constraints promote site-specific expansion of microbes that engage in cross talk with the local immune system to maintain homeostasis and promote protection. In this review, we critically assess the site-specific microbial communities that an airborne pathogen encounters in its hypothetical travel along the respiratory tract and discuss the changes in the composition and function of the microbiome in airborne diseases by taking fungal and SARS-CoV-2 infections as examples. Finally, we discuss how technological and bioinformatics advancements may turn microbiome analysis into a valuable tool in the hands of clinicians to predict the risk of disease onset, the clinical course, and the response to treatment of individual patients in the direction of personalized medicine implementation.

Evaluating the efficacy of a rotating upper-room UVC-LED irradiation device in inactivating aerosolized Escherichia coli under different disinfection ranges, air mixing, and irradiation conditions

Cost-effective and safe air disinfection methods are urgently needed in various environmental public settings. A novel UVC-based disinfection system was designed and tested to provide a promising solution because of its effective inactivation of indoor bioaerosols at a low cost. UVC light-emitting diodes (UVC-LEDs) were utilized as the irradiation source. This system has the unique feature of rotating the UVC-LEDs to generate a “scanning irradiation” zone. Escherichia coli was aerosolized into an experimental chamber, exposed to UVC-LEDs, and sampled using an impactor. Effects of air mixing (well-mixed vs. poorly-mixed), transmission range (short vs. long), and irradiation mode (stationary vs. rotating) were evaluated. The system performs significantly well under the poorly-mixed condition. The results obtained from the short disinfection range indicate that the rotating UVC was approximately 70.5 % more effective than the stationary UVC for the poorly-mixed case. Further, we evaluated the performance of the long disinfection range under a poorly-mixed situation, and the disinfection efficacy was 84.6 % higher for the rotating irradiation than that of the stationary. About 0.59–1.34 J/m2 UV dose can be used to obtain one-log inactivation of E. coli. In conclusion, the novel rotating upper-room UVC-LED system is effective in reducing indoor pathogen transmission, and our findings are highly significant to a growing field where LEDs are applied for disinfection.

Optimization of ventilation performance of side air supply for large indoor spaces using deflectors and slot air outlets

Due to the large height and span of indoor spaces, efficient indoor ventilation performance may be difficult to achieve using the side air supply for large halls, to control the indoor air pollutants or reduce the infection risk, such as the transmission of COVID-19 within the breathing zone of occupants. An efficient Ventilation Mode with Deflector and Slot air outlets (VMDS) was developed by this study. The use of a deflector with slot air outlets was introduced by utilizing jet collision and adhesion effect to accentuate the ventilation performance of the side air supply for the large space. The numerical simulation model used in this study was validated experimentally. The VMDS was compared with three other side air supply modes used in large spaces, and the results were evaluated comprehensively. The results show that VMDS is effective in reducing indoor air pollutant concentrations and transmission of infectious diseases in large spaces while satisfying the energy efficiency and thermal comfort requirements. Compared with the common side-supply and side-return ventilation modes, VMDS can reduce indoor air pollutant concentration by nearly 40%, reduce the transmission risk of infectious disease to less than 1% at a low air change rate and increase the ventilation efficiency from about 0.85 to about 1.2. In addition, VMDS can theoretically reduce ventilation energy consumption by about 85%.

Impact of SARS-CoV-2 on dentistry: a review of literature.

SARS-CoV-2 is a new Coronavirus identified as the cause of Coronavirus disease in 2019 (COVID-19). The epidemic spread in China and beyond its borders, involving 114 countries with more than 5 million dead. On March 11, the WHO declared the spread of SARS-CoV-2 to be a pandemic and encouraged nations to adopt harsh restrictive measures. Therefore, patients more and more often turn to dental offices only for emergencies. Healthcare professionals, including dentists, are at high infectious risk. In fact, the closeness to the oral cavity and nasopharynx and the use of drills or ultrasonic devices that cause aerosol release, make dental professions at high risk of bacterial and viral infections. The way patients are treated has changed. In fact, it should be mandatory to carry out a pre-treatment telephone triage and the use of mouthwashes to reduce bacterial load. In the current pandemic, it is necessary to adopt specific safety protocols that can protect dental operators as well as limit the spread of the virus. The purpose of this review is to present an overview on ways to reduce the risk of SARS-CoV-2 contagion in dentistry by focusing on the immediate situation as well as by looking towards the future. To reach the review purpose, we selected a series of studies using keywords "COVID-19" OR "SARS-CoV-2" in association with "dentistry" AND "safety protocols" AND "healthcare procedures" AND "individual protection dispositive" AND "air transmission" AND "droplet". We selected papers exclusively in English language, up to 1st January 2022. During future phases of the pandemic, everywhere in the World, it is necessary to impose all dentistry team both a serological screening and the vaccination, as already established for all health staff in Italy. For own safety, it is an important for the whole dentistry category constantly update the devices and the protocols adopted, as well as monitoring the real infectious threats, which may occur.

Occupational Health and Safety Evaluation of Compressor Room and Compressed Air Transmission Lines in an Underground Coal Mine

Günümüzde işletmelerde kompresör kullanımı çok yaygındır. Bu çalışmada bir yeraltı maden işletmesinin kompresör dairesi ve basınçlı hava iletim hatlarındaki tehlike ve riskler gürültü, aydınlatma ve kimyasal madde kullanımı başlıkları altında ele alınmıştır. Kompresör dairesinde alınan önlemler, kompresörler çalıştırılmadan önce uyulması gereken kurallar ile kullanılan kişisel koruyucu donanımlar, sağlık ve güvenlik işaretleri ile acil durum planları konularında bilgiler verilmiştir. Kompresörlere ve basınçlı hava iletim hatlarında uygulanan bakım onarım işlemleri ve periyodik kontrol konusu ayrıntılı olarak ele alınmıştır. Kompresörlerin gürültülü çalışan makinalar olması nedeniyle izolasyonlu bir çalışma ortamı sağlandığı ve kulak koruyucu donanım kullanımı ile tedbir alındığı görülmüştür. Kompresör kullanımında ihtiyaç duyulan kimyasal maddelerin kullanımında güvenlik bilgi formundaki bilgilere riayet edildiği ve kimyasallara dayanıklı kişisel koruyucu donanım kullanıldığı tespit edilmiştir. Ayrıca en son gerçekleştirilen periyodik kontrol raporunun önemli kısımları değerlendirilmiştir. Bu çalışma ile elde edilen bilgiler kompresör dairesi ve basınçlı hava iletim hatları için yapılacak risk değerlendirmesi çalışması için bir ön hazırlık niteliği taşımaktadır.

Environmental factors influencing the transmission of the coronavirus 2019: a review.

The coronavirus 2019 pandemic, induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has strongly altered healthcare systems and the economy worldwide. The lack of knowledge on this virus has led to the implementation of uncertain strategies and measures to fight the pandemic. Here, we review environmental factors that control viral transmission, such as air, temperature, humidity, food, water and sewage, insects, inanimate surfaces, hand hygiene, and social distancing. The main route of viral transmission is the respiratory tract through aerosols. Masks and social distancing are effective in ceasing air transmission. Proper cleaning of surfaces and hand disinfection are required, especially in healthcare units. Food should be handled properly, and food handlers should work based on hygienic protocols. Water and sewage transmission, and transmission through insects appear less important than other environmental factors.

Development of tricot warp knitted fabrics with moisture management for casual shirt

Warp knitted mesh fabric was usually applied to sportswear due to good air transmission, but without multilayer structure and one-way transport property. In order to solve this problem, the miss-lapping structure was applied to examine the possibility to fabricate multilayer and improve water transport in warp knitting structure. Besides, the effect of thread type and warp density on comfort properties were also exploited to enhance the moisture management. The moisture management test, water vapor permeability and air permeability were examined. Long float at the back side in structure I formed by miss-lapping could improve liquid transport and air permeability, but slightly reduce water vapor permeability. With proper density, there existed the optimal one-way transport capacity and overall moisture management. Warp density in 20 cpc was an optimal parameter of knitting process. Taking advantage of miss-lapping, sample 5 where polypropylene was partly threaded on GB1 provided best moisture management, water vapor permeability and air permeability.

Chitosan active coating on paperboard surface forming an anti‐insect grain‐based food packaging

In the food chain, the packaging is an intermediary product between the food industry and consumers. It represents a critical step in food quality preservation and the ultimate protection against insect pests. Insects may infest grain‐based food products during their packed life. Active packaging systems involve intentional interaction with food or its surroundings, and a few studies have been focused on anti‐insect packaging materials for food. The aim of this work was to develop a sustainable and active packaging material based on chitosan coating on paperboard surface incorporating lemongrass essential oil with potential action against weevil infestation in cereal‐based food packed products. The innovation is the eco‐friendly packaging development by applying natural and biodegradable compounds to prevent stored product insect infestation in the grain‐based product. The effects of chitosan and lemongrass essential oil (LG) concentrations and the number of coating layers were studied. The active packaging material was anti‐insect efficient against adult weevils in wheat grain and pasta package. The active coating reduced the air and water vapour transmission rate, and water absorption capacity improved the fat barrier while maintaining a microbial impermeability. The proposed active packaging material presented a potential application to extend the shelf life of grain‐based food products against weevil infestation.

MATHEMATICAL MODELLING OF THE VENTILATION SYSTEM OF A RESIDENTIAL BUILDING IN CONDITION THAT DIFFER FROM STANDARD

The natural ventilation systems of multi-story residential buildings are designed to meet the requirements for maximum air exchange. Their calculations under conditions significantly different from the standard, usually do not carry out and therefore do not provide measures to prevent their unstable operation. The article presents the results of the analysis of the ventilation system of a two-room section of a ten-story residential building using a mathematical model. To supply air to the apartment, ventilation valves are used. The air is removed from the apartments through two ventilation ducts. All apartments, except the last two floors, are connected to them via satellite channels. The system of equations of the model is based on the graph of the hydraulic network. It includes equations of the balance of air flow in the nodes of the graph and equations of pressure change in the links. In this case, the data presented in the catalogs of equipment manufacturers was used. The calculation results for conditions that differ from the design ones are presented, such as: significant differences in the supply air flow in individual apartments, the use of exhaust fans in some apartments, low outdoor temperature. The model under consideration allows us to explain the observed in practice air penetration through ventilation ducts from one apartment to another. It is shown that the main causes of this phenomenon are the low air transmission of modern window structures and the high hydraulic resistance of the supply valves, the use of ventilation ducts with various hydraulic resistances. The proposed approach allows already at the project stage to quantify the operation of the ventilation system in conditions that differ from standard and to optimize its design.