Air Ventilation Research Articles

Tympanic membrane metamaterial inspired multifunctional low-frequency acoustic triboelectric nanogenerator

This study introduces the Tympanic Membrane Metamaterial inspired acoustic Triboelectric Nanogenerator (TMM-TENG), which exhibits subwavelength structural dimensions and effective sound absorption within low-frequency ranges. The performance of acoustic energy harvesting is increased by replacing rigid bottom of the acoustic cavity with an elastic part and introducing a point-surface mechanism. Experimental tests employing the proposed mechanism are then conducted. The obtained results show a remarkable 2220 % increase in the output voltage of the TMM-TENG compared with the traditional approach. As for the acoustic energy harvesting performance, for a sound pressure level (SPL) of 95 dB, the peak-to-peak value of the output voltage reaches 500 V, with a measured current of 40 μA and a maximum output power of 3.05 mW. Moreover, the incorporation of an elastic part into the TMM-TENG proves advantageous in the manipulation of low-frequency sound waves. The acoustic performance of the device can also be regulated by adjusting the thickness of the elastic part. In addition, multiple TMM-TENGs with varying elastic part thicknesses are placed on a duct, and band-limited white noise is generated to evaluate the sound reduction ability without limiting the air ventilation. Furthermore, the mounted TMM-TENG allows to perform of self-powered wireless temperature sensing and acoustic telecommunication functionalities.

Occupancy Impact on Air Quality in Repurposed Museum Space

Abstract This study investigates the air quality and ventilation effectiveness in a repurposed museum space with a hybrid ventilation system in Ljubljana, Slovenia. Focusing on CO2 and particulate matter concentrations, the aim is to determine the correlation between these parameters and the suitability of the ventilation system following a change in space use. Measurements were conducted over a four-month period, analyzing data during different occupancy and ventilation scenarios. The study compares observed values with World Health Organization (WHO) guidelines, specifically targeting PM2.5, PM10, and CO2 concentrations. Findings reveal inadequate ventilation in the repurposed museum space, even with hybrid ventilation. CO2 concentrations correlated with PM2.5 and PM10 levels, suggesting CO2 monitoring as an indirect indicator of overall air quality. Recommendations include improving ventilation efficiency and limiting occupancy to ensure adherence to air quality standards.

A novel rule mining method for knowledge discovery of relationships among indoor air quality, HVAC operation and occupants’ activities

This paper presents a novel data mining method to discover the occurrence time, co-occurrence and sequential association rules among indoor air quality (IAQ), Heating, Ventilation and Air Conditioning (HVAC) operation and occupants' activities. The novelty of this work includes a peak detection method to discover the pollutants' peaks and a rule mining method with extended rule selection criteria that considers both the time lags between events and relationships among multiple events. The peak detection method aimed to use moving windows and criteria to find the candidate peaks and the non-maximum suppression to filter the overlapped candidate peaks. The proposed rule mining method is based on the Apriori and Apriori-All with the rule selection criteria extended by labeling the occurrence time to events to find the rules among various occurrence times and multiple events and by limiting the time lags among the occurrences of the events to discover the sequential rules. Two datasets, one from 70 houses and one from a single commercial building, were used to evaluate the performance of this proposed data-driven method. The results showed that 93.19 % of the peak detection results matched the peaks detected from the data records. The CO2 peaked frequently at 12:00, 17:00 and from 19:00 to 24:00. The occurrence of occupants' activities could lead to pollutants’ concentrations and pollutants peaks within 2 hours in the residential buildings. The occurrence of a high Wifi connection number was frequently followed by a CO2 peak within 2 hours in the commercial building. These findings can support the development of control strategies for building HVAC systems to achieve better indoor air quality control.

Airborne Influenza Virus in Daycare Centers.

In this study, we investigated the concentration of airborne influenza virus in daycare centers and influencing factors, such as common cold prevalence, air pollutants, and meteorological factors. A total of 209 air samples were collected from daycare centers in Kaohsiung and the influenza virus was analyzed using real-time quantitative polymerase chain reaction. Air pollutants and metrological factors were measured using real-time monitoring equipment. Winter had the highest positive rates of airborne influenza virus and the highest prevalence of the common cold, followed by summer and autumn. The concentration of CO was significantly positively correlated with airborne influenza virus. Daycare center A, with natural ventilation and air condition systems, had a higher concentration of airborne influenza A virus, airborne fungi, and airborne bacteria, as well as a higher prevalence of the common cold, than daycare center B, with a mechanical ventilation system and air purifiers, while the concentrations of CO2, CO, and UFPs in daycare center A were lower than those in daycare center B. We successfully detected airborne influenza virus in daycare centers, demonstrating that aerosol sampling for influenza can provide novel epidemiological insights and inform the management of influenza in daycare centers.

Evaluation of the airflow distribution of a vertical air ventilation system in a car cabin using PIV measurements and CFD simulations

The main goal of a ventilation system in the car cabin in general is to guarantee an adequate thermal comfort for all passengers and to enable a good air quality with sufficient air supply into the cabin. Quantifying the indoor air distribution is essential to provide the necessary thermal comfort and the required air quality. The aim of this study is therefore to analyze the subsequent airflow distribution of the vertical air ventilation system presented as a possible solution for future cars with modern interior designs. With the vertical air ventilation concept, air vents are located at the ceiling and floor area of the car cabin, as ceiling and floor regions enable a large-area influx of air into the car cabin and allow accessibility to passengers in every seating position. For the analysis of the airflow distribution of the ventilation system, Particle Image Velocimetry (PIV) measurements have been performed with a test vehicle in a climate chamber under specific conditions. Two different thermal manikins, one heated and the other unheated, have been used in the experiments. The results of the comparison between the two thermal manikins reflect a relatively low to medium impact of the human thermal natural convection on the airflow pattern around the manikin in the different air distribution modes of the vertical air ventilation system. Using the same ventilation settings, numerical simulations have been performed. The results of the numerical simulations are analyzed and compared with the results of the PIV measurements. The developed numerical model shows a good agreement with the experiments. It can hence be used for example in further studies to evaluate the thermal comfort or the air quality of the vertical airflow system as a new ventilation concept for future car interior designs.

Deep energy renovations’ impact on indoor air quality and thermal comfort of residential dwellings in Ireland – ARDEN project

As Europe's residential energy renovation programmes accelerate, field studies assessing their impact on indoor environmental quality are required to ensure maximum co-benefits to occupants' health and wellbeing. In this work, we evaluated the impact of deep energy renovation (DER) on indoor air quality (IAQ), ventilation, and thermal comfort in a sample of Irish homes (n = 12). Indoor air pollutants (IAPs), including particulate matter (PM2.5), carbon dioxide (CO2), carbon monoxide (CO), formaldehyde, radon, nitrogen dioxide (NO2), and BTEX, were measured pre and post DER. Performance of the newly installed mechanical ventilation systems was also assessed. Questionnaires and diaries were used to collect feedback regarding the retrofit and occupant activities. All occupants reported high levels of satisfaction with thermal comfort, and homes were significantly warmer post-retrofit (p < 0.0001). The DER improved indoor CO2 concentrations, indicating a positive impact on residential ventilation. However, many bedrooms were still under ventilated. PM2.5 (p < 0.0001) and formaldehyde (p < 0.05) concentrations increased post-retrofit. Higher concentrations of PM2.5 were most likely due to a combination of factors including inadequate ventilation, ingress from outdoors via open windows or doors, presence of a wood burning stove and other occupant activities. Retrofits were observed to have poor compliance with ventilation recommendations. Greater emphasis on pollutant source control along with proper installation and maintenance of mechanical ventilation systems is required to ensure DERs lead to sustainable and healthy homes.

Indoor Air Monitoring and Filtration Using Arduino-Based Plasma Technology

In public service offices in the government, special areas or rooms are provided for smoking. At the Kendal District Court Class 1B the smoking room or smoking area still uses air ventilation and fans to neutralize cigarette smoke. As a result, the smoke that is exposed to the fan in the smoking room spreads out and disturbs the health of the surrounding community or disrupts the activities of employees at the Kendal Class 1B District Court. In this case, the Kendal Class 1B District Court, especially this smoking area, needs to be handled, namely making a device that can filter cigarette smoke and monitor the condition or level of air quality in the room so that cigarette smoke does not spread outside the room and harm your health. To help the filtration system in smoking rooms, there needs to be an automatic system that is able to work when cigarette smoke in the room is at a certain level. The sensors used to detect levels of CO ( carbon monoxidant), CO2 (carbon dioxidant) in cigarette smoke are MQ-7 and MQ-135. The way this tool works, if cigarette smoke in the room reaches the threshold level of gas in the room, the fan will suck it into the filtration room, after which it will be exhaled back into the smoking room and will notify the condition of the room on the LCD monitor display.

Evaluation of ventilation and indoor air quality inside bedrooms of an elderly care centre

Ventilation and indoor air quality are important factors that affect the health of the elderly. The purpose of this study was to find effective ventilation design measures for improving ventilation and air quality in typical two-bed bedrooms in elderly care centres (ECCs). Mixing ventilation (MV), displacement ventilation (DV), zone ventilation (ZV) and stratum ventilation (SV) were analysed with twelve scenarios to find the most effective ventilation design solutions including six scenarios with curtains between the beds and six scenarios without curtains between the beds. Airflow distribution, CO2 concentration, ventilation efficiency and health risk assessment were adopted for discussion. SV was found to be an effective method for improving air quality in the ECC bedroom while also taking into account the needs and rights of elderly residents, such as privacy. Comparing scenarios with and without curtains between beds under same types of ventilation, scenarios without curtains showed a slight (≤8%) decrease in CO2 concentration in the pillow area. However, this could increase virus transmission risk and compromise elderly privacy, so it is not recommended. Regarding the scenarios with curtains between the beds, the contaminant removal efficiency (CRE) of scenarios using SV was increased by 2.58, 3.22 and 2.12 times compared to the scenarios using MV, DV, and ZV respectively. Additionally, the health ratio (HR) of SV was reduced by 46.3 %, 53.7 %, and 41.7 %. Hence, it is recommended to install curtains between the beds and apply SV in ECC bedrooms. This study can be used as a guide for systematically designing ventilation systems in ECC bedrooms. Furthermore, collaboration among environmental engineers, designers, policymakers, and the wider community is essential to develop sustainable indoor environments for the elderly.

The Effect of Suggested Ventilation Approaches After Covid-19 on The Probability of Infection, Number of Cases and Ventilation Rates in University Classrooms

After COVID-19, two ventilation approaches have been adopted for infection control. The first is the EN 16798-1 ventilation standard recommended by international organizations. The second is ventilation design, determined according to the risk of infection. This study investigated the effects of various post-COVID-19 ventilation scenarios on the probability of COVID-19 infection, the number of cases, and ventilation rates in four separate university classrooms. Ventilation rates based on infection risk and infection risk were determined by the Wells-Riley mathematical model calibrated to the SARS-CoV-2 virus. The findings showed that the EN 16798-1 ventilation standard may be inadequate in terms of infection risk in classrooms. It showed that ventilation rates determined based on infection risk may not be met by existing HVAC system capacities, even in LEED-certified schools. In possible future pandemics, current ventilation standards and air conditioning system designs in schools should be reviewed in order to control the outbreak.

Opening windows as a supplementary ventilation strategy for large classrooms in a pandemic situation: Field measurements and simulation

The coronavirus disease 2019 (COVID-19) has led to significant global health emergencies in recent years, prompting widespread recommendations across various regions for opening windows in building codes. However, official guidelines have not adequately addressed the details of window opening arrangements related to the supporting evidence from existing literature. This study investigated the risk of disease outbreaks via respiratory transmission in large university studio classrooms. It examined the effectiveness of window-door opening strategies combined with mechanical ventilation in mitigating the infection risk of respiratory diseases in such spaces. A full-scale school ventilation performance test bed was used to measure indoor airflow and CO2 distribution patterns. Comparisons were made with the numerical simulation of exhaled viral emissions. A modified Wells-Riley equation was employed to calculate inhalation exposure and disease infection risks at the room level. Measurements showed that fresh air ventilation from the mechanical system was relatively low compared to existing standards, especially in pandemic situations. The results show that opening windows can lead to a decrease to low probabilities (below 5 %) of infection risk in 85.02 % area of a classroom over an 8-h period, which demonstrates that window-opening behavior is an effective supplementary strategy for large educational spaces with mechanically ventilated systems during emergencies when active measures are insufficient for diluting diseases. Furthermore, the study reveals that maximizing outdoor air rates by opening all windows may occasionally result in adverse indoor airflow redistribution, increasing virus load from 0.0382 to 0.8926 quanta/m3 near the virus source locations.

An Experimental Study on the Efficacy of Local Exhaust Systems for the Mitigation of Exhaled Contaminants in a Meeting Room

In industrial applications, local exhaust systems have been used extensively for capturing and confining contaminants at their source. The present study investigates the efficacy of these systems in mitigating the spread of exhaled pollutants by combining them with mixing and displacement ventilation. Experiments were conducted in a simulated meeting room with six closely situated workstations, featuring five exposed persons (simulated with heated dummies) and one infected person (simulated with a breathing manikin). Six overhead local exhaust units, merged with panels, corresponding to workstations, were installed using a lowered false ceiling. Additionally, a table plenum setting for air inlets was introduced to enhance displacement ventilation effectiveness along with local exhaust systems. Results from 16 experimental cases are presented, using the local air quality index and ventilation effectiveness in the breathing zone. The local exhaust system improved the local air quality at the measuring locations closest to the infector in almost all test scenarios. The improvement, particularly significant with displacement ventilation, marked a maximum 35% increase in the local air quality index adjacent to the infector and 25% in the entire breathing zone of the tested meeting room. Moreover, the table plenum settings, coupled with displacement ventilation, further enhanced conditions in the breathing zone. Under the specific conditions of this investigation, the number of operational local exhausts had a marginal impact on mixing ventilation but a significant one on displacement ventilation tests. The efficacy of local exhaust systems was also influenced by the levels of heat gains present in the room. Overall, the study aims to contribute to ongoing efforts to identify sustainable solutions to mitigate indoor airborne diseases with a combination of supply and local exhaust units.

Living emission abolish filters (LEAFs) for methane mitigation: design and operation

As one of the most potent greenhouse gases, methane is a critical target for the near-term mitigation of global warming. Efficient, scalable, easy-to-implement, and robust mitigation technologies are urgently needed to assist in reaching methane abolishment. The goal of this research was to test the applicability of active, extremophilic methanotrophic cells as a baseline concept for engineered systems aiming at methane capturing. The system, named living emission abolish filters (LEAFs), represents an array of immobilized biomaterials capable of capturing methane directly from vent streams. The biomaterials were made using cells of Methylotuvimicrobium alcaliphilum 20ZR, a robust halophilic methanotrophic bacterium with the ability to consume methane gas at low concentrations. Several critical parameters were tested, including (i) the composition of the matrix and optimal immobilization to increase catalyst load, (ii) the stability of methanotrophic cells, and (iii) the toxicity of trace gases (i.e. CO). We found that hydrogels coated with 2.3 mg cell dry weight/cm3 methanotrophic cells represent the best-performing biomaterials. The methane reduction potential of LEAFs fluctuated from 20% to 95% and depended on the methane concentration in the gas stream and the stream flow rates. The potential for commercial-scale deployment and emissions reductions was also evaluated. Total greenhouse gas emissions (combined using the global warming potential GWP100) from an example using a ventilation air methane source over a one-year period was shown to be reduced in two LEAF scenarios by 51% and 75%. Over longer time horizons, more significant reductions are possible as consistent methane consumption can be sustained. The study highlights the overall potential of the liquid-free bio-based composite methane mitigation system. Further improvements essential for system assembly and implementations should include (a) optimization of the cell immobilization protocols to improve cell load and the shelf-life of the system and (b) implementation of matrix moldings for cell immobilization to achieve optimal gas flow and increase the cell-gas interface.

Analysis of air quality and ventilation systems in production working areas of PT. A

PT. A is a manufacturing industry specializing in plastic-based cosmetic packaging. The work area of blow molding and injection molding 1 &amp; 2 is the center of the company's main activity, involving many employees with diverse roles. The high density of work activity and heat-generating machines pose significant challenges to the workspace temperature, impacting worker health and well-being. Indoor air pollution levels, 2 to 10 times higher than outside, raise serious concerns, given people's prolonged indoor exposure. Poor air quality can lead to discomfort, health issues, and work accidents, affecting company operations and customer confidence. Three production units of PT. A were analyzed, focusing on air quality and ventilation systems. Primary data collection involved observations and interviews with four company informants regarding the ventilation system. Secondary data included direct measurements of air pollutants, dust particles, and environmental conditions by designated third parties. PT. A has implemented multiple mechanical ventilation systems to enhance airflow within the production area. Although the air quality in the blow molding and injection molding 1&amp;2 workspaces meets the standards of the Minister of Manpower of the Republic of Indonesia No. 5 of 2018, the working climate in these three production areas exceeds the specified thresholds. Engineering interventions are recommended to address this issue and improve worker safety, health, comfort, and productivity without long-term consequences.

HUBUNGAN KOMPONEN RUMAH DENGAN KEJADIAN TUBERKULOSIS DI DESA SAMURA KECAMATAN KABANJAHE KABUPATEN KARO TAHUN 2023

the lungs, but it is not uncommon for these bacteria to attack other organs of the body such as bones, lymph nodes, kidneys and other organs. The aim of the research is to determine the relationship between ventilation, floor type, wall type, residential density and humidity with tuberculosis in Samura Village, Kabanjahe District, Karo Regency in 2023. Of the 125 data on tuberculosis cases in the working area of Kabanjahe community Health Center in 2022, Samura Village is the village that has the highest TB cases in Kabanjahe sub district, Karo Regency. This research was an analytic observational study using a case control study design that analyzes casual relationships by first determining the disease (outcome) and then identifying the causes (risk factors). The number of samples in this study was 23 case samples and 23 control samples. Data analysis carried out in this research was univariate analysis and bivariate analysis. The statistical test used is the chi-square test at a confidence level of 95% (?=0.05). The results of this study indicate that there was correlation between the physical condition of the house and the incidence of tuberculosis in the ventilation variable (p-value = 0.007), occupancy density variable (p-value = 0.037), and humidity variable (p-value = 0.039). While there is no relationship between the type of floor and the type of wall with the incidence of tuberculosis in Samura Village, Kabanjahe Sub District, Karo Regency. Multivariate analysis shows that ventilation makes the highest positive contribution to tuberculosis in Samura Village, Kabanjahe District, Karo Regency in 2023. The contribution of the positive beta coefficient (?) is 2.623 with Exp (?) namely 13.773. The results of this analysis show that air ventilation at home has a 14 times risk of contracting tuberculosis.

Solutions to Detect Air Quality in a Room and Improve It

Abstract: The project focuses on monitoring and improving indoor air quality by implementing an air quality detection system. Poor indoor air quality can have detrimental effects on health and well-being, from breathing difficulties to reduced cognitive function. Therefore, it is necessary to develop methods for effective monitoring and improvement of indoor air quality. In this project, we propose the use of sensors to detect various air pollutants such as particulate matter, volatile organic compounds (VOCs), carbon dioxide (CO2), and humidity levels. Sensor data will be collected and analyzed to assess the current state of air quality. Based on the analysis, appropriate measures will be taken to improve air quality, which may include ventilation modifications, air cleaners or other interventions. The aim of the project is to create a healthier and more comfortable indoor environment for residents by ensuring an optimal level of air quality.

Analyzing global competitiveness of Turkish air conditioning industry

The global economy significantly relies on the air conditioning sector, which has been gaining increased importance worldwide and in Türkiye due to the impact of global warming, climate change, and the diminishing energy resources. As a multifaceted industry encompassing air conditioning, heating, installation, insulation, refrigeration and ventilation sector has been adapting to the growing demand for environmentally friendly and energy-efficient solutions. This study analyzes air conditioning industry of Türkiye and its sub-product groups in terms of its ability to compete internationally, spanning from 2001 to 2021. To assess competitiveness, we employed various analytical tools, including Balassa's Revealed Comparative Advantages Index (RCA), Vollrath Indices (RXA, RMP, RTA, RC), Revealed Symmetric Comparative Advantages Index (RSCA), Trade Balance Index (TBI), and Product Mapping method. Notably, there is no research that scrutinize the competitiveness of the Turkish air conditioning industry utilizing the Product Mapping. The study findings emphasize that air conditioning industry of Türkiye has competitiveness. Within the sub-product group, the analysis reveals that Türkiye has competitiveness for 11 products, a near-limit competitiveness for 3 products, and a lack of competitiveness for 10 products.

INVESTIGATION OF THE INSIDE TEMPERATURE TO ARRIVE COMFORTABLE CONDITION: CASE STUDY MECHANICAL WORKSHOP BUILDING

Mechanical workshops are considered as important buildings in faculty of engineering. It is a place for the students and teachers to get practical experiences and activities. Thermal comfort is an essential requirement in most occupied spaces because it affects the productivity, health and thermal satisfaction of the occupants. Natural ventilation, which may provide occupants with good indoor thermal comfort, and reduce energy costs, has become an important sustainable strategy in building designs. Most of the mechanical workshop buildings in countries with a hot and humid climate use a combination of natural ventilation and electrical fans are commonly used as a space cooling method to provide thermal comfort to the occupants. This article presents the results of a field measurement study that was conducted on the mechanical workshop building which is locat-ed in Faculty of Engineering, University of Aden, Yemen. The purpose of study is to investigate of the inside temperature to arrive comfortable condition of the Mechanical Workshop Building un-der the present ventilation system. The measurements were recorded within duration of one year, starting from October 2021 to September 2022 on the middle of months. The measured values were then compared to the corresponding limit as specified in the ASHRAE Standard-55. It was found that the inside temperature at the selected locations of the mechanical workshop building exceed the respective upper limits as recommended in the ASHRAE Standard-55. This shows that the existing air ventilation method via the use of natural ventilation and electrical fans in the me-chanical workshop building are not able to provide an adequate level of thermal comfort to the occupants for all the stipulated months. Therefore, an alternative ventilation method is needed to improve the thermal comfort inside the Mechanical Workshop building.

The Impact of Sick Building Syndrome and Physical Air Quality on Staff Productivity in the Hospital's Outpatient Room of Rumah Sakit Umum Daerah Haji Indonesia

Introduction: The concept of SBS as an occupational health problem is related to air pollution, inadequate ventilation, and indoor air quality in office buildings. Lighting in the RSUD Haji Building still does not meet general and local lighting standards. Complaints of eye fatigue are also felt by administrative staff in the outpatient room of the RSUD Haji Indonesia. This research aimed to examine how physical air quality and sick building syndrome give impact to officer productivity in the outpatient room of the RSUD Haji Indonesia. Methods: This kind of study used a cross-sectional design and was observational. Simple random sampling was utilized in the sampling process, and logistic and linear regression were used to analyze the data. Results and Discussion: Lighting in outpatient rooms that is 100% compliant with standards. The percentage of rooms without proper temperature norms was 21.42%. The rate of rooms with inadequate noise requirements was 17.86%. Spaces without 50% relative humidity norms. SBS symptoms: 10.3% of respondents said they always had itchy skin, and 27.6% said they frequently experienced extreme stress and exhaustion symptoms. Conclusion: There was no effect of temperature, lighting, or noise in the room regarding the sick building syndrome symptoms of officers in the outpatient room, except humidity. However, most workers felt SBS symptoms. Officer productivity was not impacted by the physical quality of the air or by sick building syndrome symptoms.

THE RELATIONSHIP BETWEEN THE PHYSICAL CONDITION OF THE HOME ENVIRONMENT AND HISTORY OF DISEASE WITH THE INCIDENCE OF TUBERCULOSIS IN THE WORKING AREA OF THE RANGKASBITUNG HEALTH CENTER IN 2023

This study aims to determine the relationship between the physical condition of the home environment and history of disease with the incidence of tuberculosis or pulmonary tuberculosis in the work area of the Rangkasbitung Health Center in 2023. This study is a descriptive correlation study with cross sectional design, which is research that explores the relationship between the physical condition of the house and the behavior of residents towards the incidence of tuberculosis. The type of data used is primary data, from the results of questionnaires and secondary data obtained from recording and reporting TB patient visit data at the Rangkasbitung Health Center. Data analysis in the study, using univariate analysis with positive TB incidence results (69.2%); Bivariate analysis showed a relationship between home air circulation and the incidence of tuberculosis (P&lt;0.028), occupancy density (P&lt;0.011), lighting (P&lt;0.015), humidity (P&lt;0.020), education (P&lt;0.002), employment (P&lt;0.006), and smoking (P&lt;0.009); and humidity factor being the dominant factor with the largest OR (OR=28.579). The results of the cross-sectional test in the study, showed a significant relationship between the physical condition of the home environment and the history of disease with the incidence of tuberculosis in the work area of the Rangkasbitung Health Center. Suggestions in this study are the need for education related to environmental factors and behaviors that cause tuberculosis, such as counseling about healthy homes with qualified ventilation, good lighting, good humidity, occupancy in an adequate place, and reducing cigarette use habits. Other factors that need to be improved, in order to support the reduction in TB prevalence rates, namely education and employment factors. Patients with pulmonary tuberculosis must also be given understanding, related must always be tried to be in a place that has adequate air ventilation and good humidity, in order to reduce the risk of the severity of TB disease which can lead to death or the duration of the treatment process.

Promoting effect and kinetic analysis of Fe-Co bimetallic doping on the LaMnO3 catalytic activity for methane combustion

To enhance the catalyst’s properties, a modified sol–gel method is developed in this study, and a unique perovskite catalyst, LaMnxFeyCo1-x-yO3, is successfully synthesized by doping Fe-Co into the lattice of LaMnO3. The catalytic activity of the synthesized catalysts is initially determined by applying them to methane oxidation. Then, the structural, chemical, and surface properties of these catalysts are systematically evaluated utilizing XRD, BET, O2-TPD, H2-TPR, SEM, and XPS analyses. The modified LaMn0.8Fe0.15Co0.05O3 is shown to exhibit excellent activity (T90 at 486.5 ℃) in methane catalytic combustion, comparable to several standard noble metal materials. Experimental findings indicate that such perovskite structures have a larger specific surface area, an elevated molar ratio of Mn4+, desirable low-temperature reducibility, and excellent oxygen mobility relative to the original LaMnO3. Meanwhile, more efficient electron transfer from Mn4+/Mn3+ redox cycles, as well as the emergence of oxygen defects, significantly contribute to the robust interaction between Fe-Co and LaMnO3. Further reaction kinetic analysis is conducted to determine changes in species components and identify possible catalytic pathways. Notably, Fe-Co co-doping leads to an improvement in the increase of lattice oxygen and CH4 adsorption. In addition, the MVK kinetic mechanism governs methane combustion over LaMn0.8Fe0.15Co0.05O3. This study provides new insights into enhancing energy conversion performance and efficient utilization of ventilation air methane (VAM) through the implementation of highly efficient perovskites.