Air Passages Research Articles

Влияние на СО2 емисия от птицеферма върху микроелементния състав на отглеждана в оранжерия маруля (Lactuca sativa)

The aim of the present study was to evaluate the effect of increased CO2 l evels a s a c ompound of mixed emissions from a poultry housing (transported by an air duct into a greenhouse), on lettuce’ trace elements content. The experiment was carried out at the experimental poultry farm of the Institute of Animal Science - Kostinbrod in May and June, 2019, for 40 days. During the experiment the following parameters were controlled and measured both in control and experimental greenhouses (lettuce groups): average level of CO2, indoor air temperature and relative humidity, - three times a week during irrigation at noon by handset IAQ Monitor SM-2100; Average level of ammonia (NH3) - three times a week during irrigation at noon by handset Aeroqual Series 200 Monitor. At the end of the experiment, soil and plants samples from both groups were taken and tested for the content of 15 microelements - Vanadium (V), Chromium (Cr), Manganese (Mn), Cobalt (Co), Nickel (Ni), Copper (Cu) , Zinc (Zn), Arsenic (As), Selenium (Se), Molybdenum (Mo), Silver (Ag), Cadmium (Cd), Tin (Sn), Mercury (Hg) and Lead (Pb) by mass spectrometry with inductively coupled plasma (ICP-MS). The obtained results show that the triple increase in the cobalt concentration in the experimental group (P <0.001) can definitely be associated with the increased photosynthesis and the expected Vit. B12 levels. Of interest are also the levels of the elements vanadium and chromium – respectively, 3.3 and 10.7 times higher in the experimental group compared to the control group (P <0.001). The content of copper and selenium in the plants corresponds to their high level in the soil, but in copper the accumulation in the experimental group is suppressed (P <0.01), while for selenium we can assume that CO2 stimulates to some extent its accumulation (P <0.05).

Experimental and numerical investigation of transparent insulation material to enhance the heating performance of an innovative Trombe Wall in Mediterranean climates

An innovative façade system in which the roof and side walls are transparent to solar radiation, with transparent insulating material parallel slats (TIM-PS) embedded between the glass façade and the solid wall, is proposed as a strategy to effectively reduce convective losses and intensify solar radiation penetration. This study proposes the validation of a model equipped with glass side walls and roof, using data provided by an experimental device. A numerical study was then carried out to investigate the effect of the TIM-PS included in the air duct and how the position of slats affects the performance of the proposed solution. The Optimal design is a T-T-W featuring with −45° TIM-PS. For the innovative T-T-W equipped with −45° TIM-PS heating duration has been extended by two hours. This original model allowed raising the thermal efficiency at 17H from 5% provided by the normal T-T-W up to 40%.

Inactivation of Bioaerosol in Natural Environments Using Tea Tree Oil

In recent years, the need for effective indoor air disinfection procedures and devices has become increasingly important. Numerous studies have highlighted the varying degrees of efficiency with which essential oils control biological aerosols. This project focuses on the antimicrobial activity of tea tree oil, a natural product from Australia, delivered using the “Unitor™ Duct Air Treatment” and “Unitor™ A/C Unit Air Treatment” solutions from Wilhelmsen Ships Service. The study explored multiple scenarios, focusing on the inactivation of bacterial and fungal aerosols in various indoor environments. The findings demonstrated that all tested products efficiently eliminated bacterial and fungal strains, with significant reductions observed even within the first 24 h of treatment. Continued operation over the subsequent six days brought airborne microbial concentrations down to just a few strains per cubic metre. These promising results highlight the potential for the further development of bioaerosol inactivation technologies that employ essential oil vapour discharge over extended periods. The tested products, leveraging the antimicrobial properties of essential oils, present a strong solution for air quality control, particularly in environments prone to high bioaerosol concentrations.

Harnessing Nature's Arsenal: Phytoconstituents targeting mediators involved in pathogenesis of Asthma

Abstract: Asthma is a persistent respiratory disorder characterized by inflammation and con-striction of the air passages, resulting in recurrent symptoms, including difficulty breathing, wheezing, coughing, and a sensation of tightness in the chest. It requires ongoing management through medications and lifestyle adjustments. The use of natural bioactive compounds in asthma management is on the rise. Researchers are increasingly exploring the potential of compounds derived from plants and herbs, such as quercetin, resveratrol, and Boswellia ex-tracts, for their anti-inflammatory and bronchodilator properties. Compounds like quercetin and resveratrol are known to reduce inflammation by inhibiting enzymes like PDE4 and LOX-5, which play key roles in asthma-related inflammation. They can additionally regulate im-mune reactions by inhibiting the secretion of pro-inflammatory cytokines like “IL-6, IL-5, and IL-4”. Additionally, some compounds, like those found in Boswellia extracts, inhibit NF-κB activation, which further reduces the production of inflammatory mediators. These natural remedies offer a promising avenue for complementing traditional asthma treatments, potential-ly providing relief from symptoms and reducing the reliance on synthetic drugs. The aim of this review is to offer an outline of well-researched plant-derived phytoconstituents that influ-ence cellular activity to control inflammatory mediators associated with asthma. Nevertheless, additional high-quality research is essential to validate the clinical effectiveness of plant-based treatments for asthma.

Optimization of ventilation and dust removal parameters in plateau extra-long tunnel inclined shaft based on orthogonal numerical simulation test method

Ventilation and dust removal system in the inclined shaft of the plateau long tunnel is an important component for ensuring safe excavation. The arrangement of wind tube and the volume of air flow have a significant impact on the movement of dust. In order to address the issues of poor ventilation and severe dust pollution in the inclined shaft of plateau long tunnels, this study establishes a dust generation and transportation model for the face of the inclined shaft based on the determination of dust source parameters and their physicochemical characteristics during the excavation process. The results indicate that the particles are predominantly spherical with an approximate diameter of 4 μm at a magnification of 500 times. The dust in high-altitude inclined shafts exhibits poor wettability, with a hydrophobic tendency during the excavation phase, making a ventilation dust removal scheme appropriate. After determining the physical parameters corresponding to the elevation of the inclined shaft, a series of orthogonal numerical simulations involving 3 factors at 5 levels were conducted. Analysis of range and variance revealed that optimal dust control is achieved when the air duct height is 5.725m, the distance from the working face is 21m, and the exit wind speed is 29.71m/s. Comparative analysis confirmed the rationality of the ventilation dust removal scheme under the optimal combination of ventilation parameters. This provides guidance for engineering and environmental management in similar construction scenarios.

Experimental and numerical research on a C-type heat exchanger in duct air conditioner under non-uniform airflow

The indoor unit of duct air conditioner typically employs an A-type heat exchanger (HX), but non-uniform airflow within the duct significantly degrades heat transfer performance. The current study proposes a C-type HX to accommodate the non-uniform airflow better. Experiments are conducted to compare the C-type and A-type HXs under varying conditions, including air volume flow rate, air velocity non-uniformity, inlet air temperature, and condensing temperature. Results indicate that as the non-uniformity of inlet air velocity increases, the heat transfer capacity of A-type HX decreases obviously. In contrast, the C-type is insensitive to the non-uniform air velocity distribution, which consistently outperforms the A-type in terms of heat transfer capacity throughout various operating conditions. Additionally, a numerical model is developed to compare the local parameters of the two HX types. The C-type demonstrates a more uniform outlet air temperature and exhibits a heat transfer capacity that is 19.1% higher than the A-type, while maintaining the identical heat transfer area and size parameters.

Irradiance modeling of tubular ultraviolet light bulbs

Clean indoor air is crucial for human lives in residential and workplace settings, including food safety and supply chains. Since the COVID-19 outbreak, disinfecting air has become vital for the public as the SARS-CoV-2 virus and other infectious diseases transmit via inhalable aerosols. Ultraviolet (UV) light is known to be effective in disinfecting air. However, it is still challenging to properly design practical UV applications with common light design software. Visible light analysis software, AGi32, assists architectural applications. AGi32 utilizes digitized luminaire IES files to model light intensity on user-designed geometry in common far-field uses. IES files are based on far-field photometry to model light intensity at different distances and angles from the source. The common application of IES files is to model visible light intensities; however, IES files generated for UV light are still rarely available. Due to the increasing need for surface and air disinfection, modeling UV light intensity using IES files may be beneficial for designing and evaluating systems containing UV light bulbs in near-field applications. There is limited information regarding the accuracy of UV modeling in AGi32 software using IES files. Therefore, the research objectives were to (1) create IES files of a UV-C germicidal lamp (254 nm) and a visible fluorescent lamp with almost identical metrics; (2) compare the IES files output with physical UV measurements inside and outside of an air duct; (3) develop correlations between light intensities of visible and UV light bulbs. Linear correlations were observed when comparing UV irradiance and visible illuminance for both measured and modeled data. The results indicated high variability between the measured and modeled light data, signifying the importance of further investigation of potential error sources and improving the accuracy of modeling.

Comparison of methods for diagnosing marine IC engines based on working medium parameters including exhaust gas specific enthalpy

Article points out methods currently used to diagnose marine engines in operation. The development of tools and programs for implementing these methods was pointed out. The problem of unsatisfactory measurement susceptibility of marine engines was highlighted. Three methods of parametric diagnosis are presented: measurement of in-cylinder parameters and in exhaust gas duct, numerical simulation due to computer software and calculations based on Wibe function. Unfitness states that were analyzed during tests are presented: reduced injection pressure, obstructed intake air duct and reduced compression ratio. The specific enthalpy of the exhaust gas within one engine cycle was determined as a new diagnostic parameter. As a supplement, thermograms of the engine in various states of inoperability were presented. The obtained results were compared and a series of conclusions derived from them were presented. It was evaluated that numerical simulation is an excellent tool for planning experimental studies. Tests on the engine in operation were found to be the most diagnostically reliable.

Medical Textiles of Self-Inflating On Air Mattress Bed and Belt for Nursing Physical Therapy Education and Training Performing a Healing Process

Medical textiles of a self-inflating air mattress bed and belt include an air chamber and a foam panel therein. The air chamber is defined by top and bottom sheet panels and a valve allowing air passage into and out of the air chamber. The foam panel includes the field of airflow passage there through, and the top and bottom sheet panels are mechanically coupled directly together via the apertures in the foam panel of the air mattress conducted to improve sleep quality. This study investigated the effect of variations in the surface characteristics of mattress beds and belts on pelvic fracture patients’ sleep quality. The present study developed a mattress bed and belt whose rigidity can be varied by controlling the amount of air in its air cells. To investigate the effect of the variable rigidity of the air mattress bed and belt on pelvic fracture patients’ sleep quality, participants (women, ages 13-45) were instructed to sleep on the air mattress bed and belt under different conditions, and their sleep quality was subjectively and objectively investigated. Subjectively, sleep quality is assessed based on the participants’ evaluations of the depth and length of their sleep. Objectively, medical textiles for pelvic fracture patients and mattress bed and belt specifications are estimated using the sleep stage information obtained by analyzing the movements and brain waves of the participants during their sleep. A subjective assessment of the sleep quality demonstrates that the participants’ sleep was worse with the adjustment of the air mattress bed and belt.

Exergy Efficiency and Energy Efficiency of Double Air Pass Solar Tunnel Air Dryer: A CFD Analysis

This work presents, the computational fluid dynamics simulation of a forced convection double air pass solar tunnel drying system to study the temperature distribution, the flow behaviour of the air stream, and the exergy performance. Realizable k-epsilon non-equilibrium wall function turbulence model, discrete ordinate radiation model, and species transport were used. The average temperature, thermal efficiency, and exergy efficiency were found to 59.2 oC, 30%, and 9.41%, respectively. The result revealed that the uniform temperature and velocity distribution throughout the heating and drying chamber. Therefore, the newly developed double air pass solar tunnel dryer enhances the air temperature and the exergy performance leads to the increment of drying rate and reduction of drying period.

Geometric Evaluation of an Oscillating Water Column Wave Energy Converter Device Using Representative Regular Waves of the Sea State Found in Tramandaí, Brazil

Aiming to contribute to studies related to the generation of electrical energy from renewable sources, this study carried out a geometric investigation of an oscillating water column (OWC) wave energy converter (WEC) device. The structure of this device consists of a hydropneumatic chamber and an air duct, where a turbine is coupled to an electrical energy generator. When waves hit the device, the air inside it is pressurized and depressurized, causing the air to flow through the duct, activating the turbine. In this sense, the present study used the constructal design method to evaluate the influence of the ratio between the height and length of the hydropneumatic chamber (H1/L) on the mean available hydropneumatic power (PH(RMS)). Fluent software was used to perform numerical simulations of representative regular waves from the sea state in the municipality of Tramandaí, southern Brazil, impacting the OWC. Thus, it was possible to identify the geometry that maximized the performance of the OWC WEC, with (H1/L)O=0.3430, yielding PH(RMS)=56.66 W. In contrast, the worst geometry was obtained with H1/L=0.1985, where PH(RMS)=28.19 W. Therefore, the best case is 101% more efficient than the worst one.

Experimental study of the factors influencing the uniformity of an air curtain and numerical simulation of the factors influencing its dust barrier effect

This study analyzes the influence of air curtain diameter and internal duct structure on the uniformity of an air curtain using Fluent numerical simulation combined with an experimental method after actual measurement of relevant parameters at the construction site, and simulates the best dust insulation parameters of a uniform air curtain. As the diameter of the air curtain supply duct increases and the internal air duct structure is reasonably designed, the axial static pressure of the air curtain generator and the air velocity at the curtain outlet are more uniform, which forms a higher strength of the air curtain. The best dust separation parameter of the uniform air curtain is the vertical downward generated air curtain with an outlet air velocity of 12 m/s and an outlet strip slit width of 80 mm, in which the dust separation efficiency could reach about 79.5%.

THE STUDY OF THE TECHNICAL CONDITION OF GONDOLA CARS

The article presents the results of the analysis of the technical condition of gondola cars owned by the transport operator BGS rail. The composition of the model range of the car fleet was analysed. It is shown that 14 % of gondola cars produced by Uralvagonzavod have an average service life of over thirty years and have exhausted their service life. Gondola cars of models 12-757 and 12-753 of Kryukov Carriage Works have also exhausted their service life. A positive factor is the presence of innovative cars model 12-7023 produced by KVSZ and 12-4106 model produced by PJSC Dneprovagonmash in the car fleet. Their average age is 6.5 years.An analysis of the main causes of failures that caused the car to uncouple from the train along the route was carried out. In the first place are damage to body elements. This is followed by failures of automatic brakes and wheel sets.Among the damage to gondola car bodies, the first place is taken by malfunctions of the locks on the unloading hatch covers, followed by cracks and breaks in the upper and vertical sheets of the frame cross beams. Broken weld seams of braces and broken linings also pose a serious danger.Failures of auto brakes are caused by loosening of air duct pipes, brake equipment and welded shoes. The main causes of damage to wheel pairs are unacceptable wear of the flange. Among axle box assemblies, the vast majority of failures are caused by excessive heating of the bearings.Failures of automatic coupling equipment are most often caused by fractures of the centering beam and breaks (cracks) of the pendulum suspension. Cracks and other malfunctions of the automatic coupling body are also observed.The bogies mostly have broken springs and mismatched sliding clearances. Also, a quarter of the uncoupled bogies have expired service life of their elements. The average recovery time for gondola cars was analyzed. Due to malfunctions of axlebox units, cars are under repair for more than 15 days, due to failures of wheel pairs - 11.55 days. The least time is spent on auto brakes – 4.2 days.An analysis of the damage to the bodies of various gondola cars models showed that gondola cars of models 12-9745 and 12-9790 are in the worst technical condition. The least susceptible to damage are the «innovative» gondola cars of models 12-7023 and 12-4106.

Otomatisasi Penyemprotan Polyester Menggunakan Kawasaki Cobot dengan Human Machine Interface (HMI) Berbasis Web

Brago Luchttechniek BV is a company specializing in the production of PIR (Polyisocyanurate) air ducts, facing challenges in maintaining accuracy and consistency in the polyester insulation spraying process on its products using Kawasaki collaborative robots (cobot) for automation. To address these challenges, this study designed a web-based Human Machine Interface (HMI) to automate the polyester insulation spraying process on PIR air ducts using the Kawasaki Cobot. A web-based HMI was chosen for its ease of development, flexibility, and integration capabilities with modern technology. This HMI uses the TCP/IP protocol to send real-time command signals to automation devices such as the Kawasaki Cobot and devices connected to the Programmable Logic Controller (PLC). Testing results demonstrated an improvement in the spraying process efficiency, reducing the time from 15–18 minutes conventionally to 5–7 minutes with the web-based HMI automation. Additionally, the web-based HMI successfully communicated with other devices connected to the robot, such as the conveyor belt and rotating table, via TCP/IP protocols, with each device having its own ID and IP address to facilitate linear message delivery, prevent collisions, and minimize errors. After eight successful automation tests on four different products, the system operated smoothly and systematically through the available HMI controls. The system was also evaluated by four respondents, with an overall score of 4.33 out of 5, indicating a high level of satisfaction.

A novel ventilation method: Experimental measurement and numerical simulation of vertical single-row inclined slit ventilation

Existing ventilation technologies often struggle to balance the limited airflow supply with the demands of indoor ventilation and air circulation in winter. This paper introduces a novel ventilation method, vertical single-row inclined slit ventilation (VSISV), which channels airflow through multiple inclined slits spaced at specific intervals along a vertical supply air duct. By ensuring continuity of the upstream and downstream slit jets, a continuous downward airflow is formed, enhancing both winter ventilation performance and indoor air circulation. The method was experimentally measured, with a focus on comparison to the IJV system. At the same airflow rate, it not only efficiently transports the supply air heat from the upper indoor area to the floor but also exhibits strong horizontal diffusion capability. The RNG turbulence model was selected for numerical simulation, focusing on indoor thermal comfort, air quality, and energy-saving potential. The results indicate that, at the same airflow rate, this method effectively maintains high indoor thermal comfort, directs airflow downward from the ceiling, reduces thermal stratification in the upper zone, achieves a more uniform and elevated indoor temperature, enhances indoor air quality, and demonstrates substantial energy-saving potential. This provides valuable insights for energy conservation, emission reduction, and the optimization in winter building ventilation systems.

მიწისქვეშა ავტოსადგომების კვამლისაგან დაცვა ხანძრის დროს

The work examines current issues of fire, sanitary, hygienic and environmental safety of ventilation of underground parking lots. It has been established that, according to European standards, smoke removal systems with jet fans act much more efficiently than air ducts, quickly displacing smoke and exhaust gases towards the air intake grilles, from where and they come out. The design and parameters of the ventilation system are selected based on its ability to quickly and safely ensure the evacuation of people through smoke-free exits, as well as provide air parameters in the parking lot that meet the requirements of the design and installation of a ventilation unit in accordance with industry regulations of Georgia.

Influence of trains meeting on the ventilation performance of equipment compartment with independent air duct in high-speed train: numerical and experimental study

AbstractDuring the train meeting events, train equipment compartments are exposed to the worst pressure changes, potentially affecting the ventilation performance of equipment, particularly for electrical facilities equipped with independent air ducts. In this paper, a two-step method is used for numerical computation: (1) obtaining the temporal and spatial transient node data of the flow field sections during the train-passing simulation and (2) using the data as the input data for the equipment compartment simulation. In addition, this paper also compares the difference in equipment ventilation between the single-train and train-passing scenarios in real vehicle tests. The results indicate that the primary factors influencing ventilation effectiveness are the aerodynamic compression and deceleration of airflow induced by the other train’s nose, as well as the instability of the external flow field in the wake of the other train. During train crossing, the air is forced into the air duct, with a maximum ratio of the airflow in-duct to the airflow out-duct reaching 3.2. The average mass flow falls below the rated mass flow for the converter. Compared to the rated air volume of converter, the maximum suppression rates obtained from testing and simulation are – 24.5% and – 16.8%, respectively. Compared to the single-train operation, the maximum suppression rates obtained from testing and simulation are – 15% and – 18%, respectively. These findings provide valuable insights into the design and operation of high-speed trains.

Optimization of hydraulic structure and well flushing parameters of a truncated cone drill bit for drilling shaft sinking

ABSTRACT Based on a research method combining numerical simulations and model testing, a numerical model and test platform for gas lift reverse circulation multiphase coupling in well washing were developed. The hydraulic structure and well washing parameters of a φ5 m truncated cone bit used in the Beifeng well at Taohutu Coal Mine were optimized, and the distribution law of the well washing flow field was determined. The findings revealed that: (1) with a bit taper of 40 and a length-diameter ratio of 0.32 for the truncated cone, the hydraulic structure was optimal. Compared with the original bit structure, the axial speed of mud at the slag suction port increased by 15.9%, and the average sliding speed of mud at the inclined rock surface increased by 63.2%. (2) The multiphase fluid in the slag discharge pipe flowed successively in the form of “low-speed stable two-phase flow” and “high-speed disordered three-phase flow,” while the multiphase fluid in the horizontal and inclined bottom holes flowed predominantly in radial and tangential patterns, respectively. (3) The optimal parameter combination for efficient well washing with the truncated cone bit included a bit rotation speed of 8 r/min, a gas injection rate of 5600 m3/h, an air duct sinking ratio of 0.79, and a mud viscosity of 176 mPa·s, with bit rotation speed being the most significant factor affecting effective washing efficiency. These results could provide a valuable reference for improving the efficiency of drilling and well flushing in Jurassic strata of western China.

SPLIT DUCT AC LEAKAGE MONITORING SYSTEM VIA GOOGLE SHEETS

General Background: Split duct air conditioners are prone to leaks, often resulting from corrosion in water catchment systems, which can lead to significant operational hazards such as electrical fires. Specific Background: Given the prevalence of these issues, there is an urgent need for effective monitoring solutions to maintain optimal air conditioner performance and prevent leaks. Knowledge Gap: Current monitoring systems lack integration with real-time data reporting mechanisms that can alert users promptly to potential issues. Aims: This research aims to develop a monitoring device utilizing NodeMCU ESP8266, water level sensors, and Google Sheets to enable real-time monitoring and management of water levels in split duct air conditioners. Results: The device successfully operates by turning on the fan when water levels are below 2 cm and activating the pump when levels exceed this threshold. The data is continuously sent to Google Sheets, allowing for easy monitoring and management. Novelty: This study presents a novel approach to air conditioner leak monitoring by integrating IoT technology, offering an efficient and user-friendly solution for residents. Implications: The developed monitoring tool significantly enhances the ability to detect and manage potential leaks in real time, thereby improving safety and operational efficiency. Future research should focus on enhancing sensor accuracy through specialized equipment and exploring alternative IoT platforms for improved data visualization, thereby providing users with an even more effective monitoring experience.

Numerical simulation of falling film dehumidification with rectangular cylinder insertion modification at different elevations

ABSTRACT A falling film dehumidifier is one type of desiccant-based dehumidifier with superior performance and has a simple design and working mechanism. Geometric modifications of falling film dehumidifiers can impact their fluid flow and effectiveness. For further investigations, a CFD (Computational Fluid Dynamics) numerical simulation was carried out on the dehumidifier geometric innovation equipped with a rectangular cylinder with variations in different height positions. Falling film dehumidifier with four variations of rectangular cylinder height positions (3/12 h, 5/12 h, 7/12 h, and 9/12 h) was analyzed to determine its impact on dehumidification performance for each incoming airflow of 0.5 m/s, 1 m/s, and 1.5 m/s. Based on the results, it was evident that adding a rectangular cylinder to the humid air passage can change the flow characteristics, enhance the distribution rate of mass and air temperature, and ultimately enhance the dehumidification performance. The decrease in humidity and temperature increased by 11–14% and 11–27%, respectively, for the air velocity range of 0.5–1.5 m/s. In addition, the dehumidification performance was obtained to increase by 11–14% at the same air velocity range. Variations in the position of a rectangular cylinder show different results, where the lowest position delivers the best dehumidification performance.