Inside Air Research Articles

Design and Development of Silent Air Purifier and Humidifier Using Water Filter

Abstract: In 2021, air pollution has gone beyond all limits. According to the WHO, 7 million people die annually as a result of air pollution. A whopping 91 percent of the world's population is now exposed to air pollution due to its wide distribution. This also implies that the air within your home is contaminated. In order to address this problem, we have developed a small air purifier that employs water as an air filter rather than pricey filters. Additionally, it functions as an air humidifier and can be used as an oil diffuser, both of which promote relaxation and the elimination of some airborne bacteria and viruses. Homes in larger cities are often affected by poor interior air quality, which is a result of an expanding industrialization that contaminates the air we breathe with pollutants including industrial dust, smoke, and other particles from traffic. Utilizing an air purifier to remove these particles from the air within the user's home is the best option from the user's point of view. People who have allergies can also use an air purifier to reduce their irritation. The design and development of the next-generation indoor air purifier is the subject of this thesis. The project was carried out using a human-cantered design process, and a patient was the end outcome.

Effectiveness of excess gas method for the preparation of hydrate-bearing sediments: Influence and mechanism of moisture content

Excess gas method (EGM) was used to synthesize hydrates in the prepared sediment samples with different moisture contents. During the process of hydrate formation, the inside temperatures and air pressures in the upper and lower part of the samples were monitored. Meanwhile, the content of various types' pore water in the samples with different moisture contents were measured. Based on the growth mechanism of hydrates and the composition feature of pore water, the influence and mechanism of the type and content of pore water on the effectiveness of EGM for the preparation of hydrate-bearing sediment samples (HBSs) were discussed. The results show that the saturation degree of hydrates increases from 19.58% to 29.03% when the moisture content of the samples increases from 5% to 9%, the air pressures in the upper and lower part of samples are similar, and the hydrate distribution is relatively uniform. When the moisture content increases from 9% to 12%, the gas pressure difference between the upper and lower part of the samples increases from 0.25 MPa to 2.55 MPa, the distributions of hydrates become inhomogeneous, implying that the increased water has an important influence on hydrate formation. The bound water content (the quality ratio of bound water to soil particles) is in the range of 0.48%–0.54%, and almost unchanged with the increase of water content. When the unbound water content (the quality ratio of unbound water to soil particles) increases from 4.42% to 11.38%, the hydrate saturation degree difference between the upper and lower part of the samples increase from 1.91% to 19.74%. Therefore, the unbound water content has a significant impact on the process and effectiveness of hydrate formation. The unbound water saturation degree (the volume ratio of unbound water to pores) of 25.66%–33.60% is beneficial to the preparation of HBSs with a higher saturation degree and uniform distribution of hydrates for the studied clayey sand. The results can provide some reference for the effective formation of hydrates and the study of hydrate growth mode in samples.

Цифровое моделирование аэроупругого взаимодействия подвижного состава с портальными сооружениями перевальных тоннелей

Purpose: Development of mathematical models allowing to investigate the processes of aeroelastic interaction of a rolling stock with portal buildings of passover tunnels in dynamic and quasi-stationary setting with the use of deformable mobile nets and FrozenRotor methods. Methods: we present mathematical models and ways of their realization in two- and three-dimensional setting in program complexes Comsol Multiphysics and Solid Works Flow Simulation on the basis of numerical solution of Reynolds averaged NavierStoks Method (RANS) method equations. Results: The results of numerical research of velocity and pressure fields nearby tunnel portal zone, obtained with the help of developed mathematical models for the case of rolling stock entrance into a tunnel, ‘re given. Practical importance: It’s revealed that at train entrance into a tunnel, air mass runaway by a rolling stock is made with significant delay owing to effect of viscous friction force between an air and tunnel walls as well as inside air volume which fills a tunnel.

Liquid Metal Vacuoles

AbstractConventional bubbles are generally made of an outside water film and the interior air, and their formation and rupture involve rich scientific knowledge. An intriguing question is what would happen if the water film and air of such bubbles were replaced by completely different fluids? Here, a high‐surface‐tension liquid metal‐solution bilayer is introduced into the two‐phase interface system, and a new conceptual hybrid vacuole consisting of a liquid metal outer membrane and inner solution core is proposed and demonstrated for the first time. Through tuning the filling volume of the liquid metal, various vacuolar structures with diverse interfacial morphologies are constructed. Such vacuoles can maintain long‐term stability via adjusting the composition of the solution, which is a mixture of surfactant and alkali. If switching glass substrate to graphite, liquid metal vacuoles would become more robust and exhibit further abundant individual and collective behaviors, which are mainly attributed to the firmer bonding strength between the two‐phase interfaces. In addition to interpreting the generation and maintenance mechanisms of the vacuole, different rupture processes are also presented and disclosed. The current findings on the liquid metal‐solution hybrid vacuoles are expected to enrich the content of liquid metal interfacial science, and will stimulate further promising applications in the emerging engineering fields.

Evaluation of Typical Volatile Organic Compounds Levels in New Vehicles under Static and Driving Conditions.

In modern societies, the air quality in vehicles has received extensive attention because a lot of time is spent within the indoor air compartment of vehicles. In order to further understand the level of air quality under different conditions in new vehicles, the vehicle interior air quality (VIAQ) in new vehicles with three different brands was investigated under static and driving conditions, respectively. Air sampling and analysis are conducted under the requirement of HJ/T 400-2007. Static vehicle tests demonstrate that with the increasing of vehicle interior air temperature in sunshine conditions, a higher concentration and different types of volatile organic compounds (VOCs) release from the interior materials than that in the environment test chamber, including alkanes, alcohols, ketones, benzenes, alkenes, aldehydes, esters and naphthalene. Driving vehicle tests demonstrate that the concentration of VOCs and total VOCs (TVOC) inside vehicles exposed to high temperatures will be reduced to the same level as that in the environment test chamber after a period of driving. The air pollutants mainly include alkanes and aromatic hydrocarbons. However, the change trends of VOCs and TVOC vary under different conditions according to various kinds of factors, such as vehicle model, driving speed, air exchange rate, temperature, and types of substance with different boiling points inside the vehicles.

Deep learning and computer vision based occupancy CO2 level prediction for demand-controlled ventilation (DCV)

The present study investigated the potential of the application of a live occupancy detection approach to assist the operations of demand-controlled ventilation (DCV) systems to ensure that sufficient interior thermal conditions and air quality were attained while reducing unnecessary building energy loads to improve building energy performance. Faster region-based convolutional neural network (RCNN) models were trained to detect the number of people and occupancy activities respectively, and deployed to an artificial intelligence (AI)-powered camera. Experimental tests were carried out within a case study room to assess the performance of this approach. Due to the less complexity of people counting model, it achieved an average intersection over union (IoU) detection accuracy of about 98.9%, which was higher than activity detection model of about 88.5%. During the detection, the count-based occupancy profiles were produced according to the real-time information about the number of people and their activities. To estimate the effect of this approach on indoor air quality and energy demand, scenario-based modelling of the case study building under four ventilation scenarios was carried out via building energy simulation (BES). Results showed that the proposed approach could provide demand-driven ventilation controls data on the dynamic changes of occupancy to improve the indoor air quality (IAQ) and address the problem of under- or over-estimation of the ventilation demand when using the static or fixed profiles.

Transport of persistent organic pollutants: Another effect of microplastic pollution?

AbstractOver the past decade, the number of studies examining the presence and effects of microplastics in the environment has drastically increased. Works seeking to identify these particles have proven beyond doubt that microplastics constitute a generalized pollution affecting all environmental compartments, from inside air to arctic snows. Studies on their potential ecotoxicological impacts were more nuanced but many have shown deleterious effects when these microplastics were associated with persistent organic pollutants. This primer mainly focuses on POP sorption and transport by microplastics in the aquatic environment and the possible toxic effects that result from it. Indeed, the associations between microplastics and persistent organic pollutants are very common in the environment. If the mechanisms of interactions are well known, they depend on many factors and their significance in the environment can be very variable in time and space. Indeed, these interactions depend on both the plastic particle (polymer type, crystallinity, particle size, shape, specific area, and functional groups/polarity) and the pollutant (hydrophobicity, functional groups) but also environmental factors (microorganism population, salinity/ionic strength, pH, dissolved organic matter concentration, and temperature). Changes in the interactions between pollutants and microplastics can result in pollutant release in the aquatic environment and potential toxic effects. However, apart from specific situations, the role of microplastics as local source of exogenous molecules (PAHs, PCBs, etc.) is rarely significant because the limited amounts of involved pollutants. It is much less negligible for endogenous chemicals that enter into the initial composition of the plastic (phthalates, biocides, etc.).This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems Science of Water > Water Quality

Analysis of the Thermal Characteristics and Energy performance of Electro Chromic Glazing window

Windows and shading devices occupy an essential part between inside and outside environment of buildings, for providing interior air quality and optimization of lighting and HVAC energy consumption. This paper aims to perform the thermal performance of double pane Electrochromic window (ECW) using Finite Element Method and the energy performance using the Building Information Modelling (BIM) tool. The thermal model of the ECW is simulated in COMSOL Multiphysics. Double pane glass with and without electrochromic (EC) layer is analyzed to obtain the average and maximum surface temperature between the top and bottom layers of the glazing. It is observed that the maximum temperature gradient is observed with EC layer. The energy performance with a double glazing and ECW for warm and humid climate is evaluated using eQUEST DOE tool. A 30 % reduction is observed in the annual energy consumption with an ECW compared to that with a double-glazing window. In addition, during the monthly evaluation of energy consumption, there is 10% reduction with the ECW compared to baseline. The appreciable thermal characteristics and the energy performance of the EC glazing proves it to be an alternative solution for normal window glazing in automated buildings for thermal comfort and lesser cooling load demand.

Impact of environmental factors on energy balance of greenhouse for strawberry cultivation

This study elucidated the effects of passive solar greenhouses on strawberry cultivation in temperate areas. The energy required to heat the greenhouse was calculated. Furthermore, the results of a field test performed in a temperate area in central Japan were presented. Environmental conditions such as the ambient temperature, solar radiation, and relative humidity were experimentally investigated. The results of this study indicate that the maximum temperature difference between the inside and ambient air temperatures was 16.4 °C during the evaluation period. The maximum reduction in solar radiation through a transparent vinyl sheet in the greenhouse was approximately 30% when compared with the ambient solar radiation. Additionally, heating requirements were estimated to achieve optimal cultivation conditions in the future. The monthly heating requirement of the greenhouse was between 60.0 and 327.6 MJ/(m 2 ･month), and the energy requirement for heating was found to be maximum in the extremely cold month of January. The energy required for controlling the optimum environment for sensitive plant cultivation was proposed. The proposed evaluation methods can also be applied to other regions for cooling. • Effect of passive solar greenhouse on strawberry cultivation is investigated. • Field test is performed in a temperate area in central Japan. • Greenhouse provides thermal comfort for strawberry crop during winter. • Heat energy required for optimum cultivation in an area is estimated. • Validity of energy analysis proposed in this study is demonstrated.

Real-Driving Measurement of Vehicle Interior Air Quality and Cabin Air Filtering Performance by Using Low-Cost Sensors

Real-Driving Measurement of Vehicle Interior Air Quality and Cabin Air Filtering Performance by Using Low-Cost Sensors

Acoustic oscillations of drag-reducing air pocket under fast boat with stepped bottom

One promising method for reducing water resistance of marine vessels is to create air pockets on their wetted hull surface. However, such pockets can experience acoustic oscillations when excited by periodic sea waves. These oscillations may reach high amplitudes at resonance conditions, when the air-pocket natural acoustic frequency approaches to the excitation frequency. This can lead to excessive air leakage from the pockets and eventual disintegration of air cavities, resulting in a loss of their drag-reduction effectiveness. A reduced-order acoustic model has been developed to analyze this process. Using realistic hull and air-pocket parameters, the model was applied to simulate acoustic oscillations of an air pocket under a fast boat. It is shown that increased damping inside air cavities can limit oscillation magnitudes to acceptable levels. Another strategy involves quick acceleration of the hull, so that time spent near the resonance condition is insufficient for substantial growth of high-amplitude acoustic oscillations. Active acoustic control can also be used to suppress the oscillations. [Work supported by the U.S. National Science Foundation under Grant No. 1800135.]

The potential of facade greening in mitigating the effects of heatwaves in Central European cities

This study investigates the potential of living walls in improving the climatic quality in the urban environment. To achieve this goal, numerical simulations using the urban microclimate modelling tool ENVI-met were conducted to analyse the distribution of air temperature, mean radiant temperature (MRT), relative humidity, and wind speed in a residential block in Stuttgart, Germany. The impact of the living wall on the interior air temperature was investigated as well. Before the simulations were conducted, the model was first validated against measured data collected in Weimar, Germany. The validation showed a fairly good agreement between the measured and simulated air temperature, MRT, relative humidity, and wind speed with an averaged respective mean absolute error (MAE) of 0.72 K, 2.67 K, 3.98%, and 0.30 m/s. The simulation of the residential area in Stuttgart indicated that facade greening has only a little impact on air temperature (−0.57 K). Yet, a reduced MRT by up to 3.04 K and a reduced interior air temperature by up to 3.8 K were observed. The living wall also had an impact on the relative humidity among the buildings, which was increased by a maximum of 5.07%. Only a marginal impact on airflow between buildings was observed when facade greening was implemented. Yet, air velocity directly in front of the foliage was reduced by an average of 0.25 m/s.

Evolution of and Disparity among Biomimetic Superhydrophobic Surfaces with Gecko, Petal, and Lotus Effect.

It is desirable to turn one kind of superhydrophobic (SHPO) surfaces into another by changing surface topography alone and attaining solid surfaces with tunable properties. Herein, gecko-, petal-, and lotus-like SHPO surfaces, composed of ZnO tetrapods and polydimethylsiloxane, are realized by adjusting the roughness factor and length scale of roughness, while keeping the surface chemistry the same. Afterward, water droplet sliding and impacting are investigated. The surfaces behave similarly in spreading but deviate from each other in sliding, receding, jetting, and rebounding due to their different adhesive properties. Moreover, the disparity between surfaces with petal and lotus effects is well explained by Furmidge's and Young-Dupre equations. On the other hand, these formulas fail to elucidate the surface with gecko effect because of its inside sealed air that produces negative pressure upon droplet motion. This paper provides a facile topography evolution path and a manifest correlation between topography and performance in water droplet dynamics for SHPO surfaces with gecko, petal, and lotus effects.

Design, modeling, and testing of a soft actuator with variable stiffness using granular jamming

AbstractSoft robots combine the load-bearing capability of rigid material with the resilience, shape-shifting capabilities of soft materials. This paper presents a novel soft actuator with stiffness variation using particulate jamming technology. We design a hybrid composite structure consisting of driving layer and jamming layer. The driving layer with the arc air chamber aim to achieve large bending deformation. A membrane containing particles is integrated with driving layer to module its stiffness. The influence factors of stiffness variation were analyzed from energy of point of view. The dependence of granular attributes on the stiffness of the actuator was studied. Furthermore, we illustrated influence of stiffness changes on the kinematic and dynamic performance of the soft actuator. The experimental results showed these performance indexes are twofold. On the one hand, the structural parameters have significant effect on the bending angle, but on the other hand they have little effect on the end force. We found that flow resistance inside air chamber results in bending morphology variation. The dynamic response subjected to a square-wave air pressure was analyzed to exhibit the actuator’s transient and steady vibration behavior. The actuator with greater stiffness has faster responsiveness, but smaller range of motion. These conclusions are helpful to adjust the stiffness behavior and to improve motion performance.

Virtual Twin for the Calculation of the Power Demand of the Interior Air Conditioning

Virtual Twin for the Calculation of the Power Demand of the Interior Air Conditioning

Feasibility of winter cultivation of fruit vegetables in a solar greenhouse in temperate zone; experimental and numerical study

Feasibility of winter-cultivation of fruit vegetables was studied in a solar double plastic covered greenhouse in a temperate zone. An experment for 24-hour-course including a cold night was performed and an unsteady numerical model was developed to predict microclimate in the greenhouse. Sensible heat term with separated air and leaf temperatures was applied to energy equation. Modeling of plant transpiration and outside boundary conditions were accomplished by applying a user defined function added to FLUENT. Comparisons between measured and simulated air/leaf temperatures showed a good agreement for the 24-hour-course. Simulations were performed to examine the feasibility of ensuring the inside air temperature higher than 12 ℃ (the lowest temperature limit for fruit vegetables) in inner greenhouse during the coldest winter night. When covering both the outer and inner films with quilts, it could overcome the night with the lowest outside air temperature of −18.6 ℃. A necessity of heat shield for north wall outside surface was confirmed. Results show that the double plastic covered greenhouse can be a good passive solar system for winter-cultivating the fruit vegetables in some temperate zones.

Fungal Allergen in Dwellings During Rainy Season and Their Impact on Human Health

The wet season is the main period of vegetation growth. Mould is seldom the problem; rather, moisture is the problem and the mould is the visual manifestation of the problem. The concrete foundation wall behind the drywall remained colder than the interior air, and water condensed on the drywall providing sufficient available water to promote widespread growth of microbes. This Present study was conducted during the rainy season of 2013. Two stage Anderson air sampler was used for one year i.e., from June 2013 to September 2013. Air sampling was done fortnightly, for ten minutes. The main aim of this work is to report total fungal flora found in the indoor and outdoor environment of home in Jabalpur city and to perform skin prick test to detect fungal sensitization. During this study Aspergillus sp., Cladosporium sp. and Alternaria sp. was the dominating genera found in the rainy season and patients are more sensitive to Cladosporium sp. and Alternaria sp.

Solar outdoor air purifier with air quality monitor

Pollution is increasing very effectively in the world. It must be reduced the present pollution levels by the deadline even though the long-term solution to the pollution problem is to identify and reduce pollution sources. The use of air purifiers is the most effective method of reducing pollution. Regular interior air purifiers, however, are little, low-power gadgets that lack the necessary filtering capacity for outdoor environments. Additionally, there is a problem with outdoor machines' power supplies. Therefore, it has created a solar outdoor air purifier that is energy independent and built for outside filtration. It is powered by solar panels. A powerful suction fan at the bottom of our solar air purifier draws air up through a layer of pre-filters, High-Efficiency Particulate Absorbing (HEPA) filters, carbon filters, and Ultraviolet (UV) lights to remove gases and (Particulate Matter) PM 10 and PM 2.5 pollutants. Prefilter, HEPA layer, Active Carbon Filter, and UV light make up the first of the purifier's four purification layers. The combination of these four filters results in the best filtration, sucking in a lot of air and clearing it of dust particles utilizing centrifugal air force.

Light drives vegetative phenology of

Despite Orchidaceae is a key component of the epiphytic flora of tropical and subtropical forests, phenological studies of this group are rare, mainly due to technical difficulties in observing epiphytes, the reduced abundance of wild specimens, and to the evergreen characteristic of these plants. We monitored shoot and root production of translocated young plants of the epiphytic orchid Cattleya intermedia Graham at the edge and in the interior of a subtropical Atlantic Forest fragment, and investigated their relationship with temperature, luminosity, photoperiod, rainfall and air humidity. Individuals propagated in vitro were translocated in the spring and inspected monthly for 3 years for shoot and root production. Shoot production at the edge of the forest was positively related with photoperiod and luminosity. In the interior, this relationship was characterised by a 1-month time delay. The highest concentrations of plants with shoot production occurred in spring and summer in both environments. Interior plants were more likely to produce roots in spring and summer, while edge plants were more likely to produce roots in summer. Edge plants produced fewer roots when rainfall was high, while interior plants produced more roots when interior air humidity was high. The influence of light availability for translocated plants was demonstrated by the different responses of shoot growth at the edge and in the interior of the forest and by the relationship with the seasonal variation of this variable. Thus, light becomes a key factor for the establishment of translocated C. intermedia and must be considered in the choice of their habitats.

Energetic and economic analysis for improving greenhouse energy efficiency

Protected agriculture is one of the prominent agricultural techniques. It allows for creating an adapted microclimate to the plant growth, which leads to high quality and off-season production. Instead, a significant amount of energy is required. This study aims to provide the potential of energy saving based on the optimal selection of the greenhouse design under Fez City’s climatic conditions (Morocco). For this purpose, a dynamic model of a gothic-arch-shaped greenhouse is created in EnergyPlus environment. The impact of four different orientations (0°, 90°, 45° and - 45°) on greenhouse energy needs is first investigated. The selected design is further improved by using a thermal insulation blankets system operating during the coldest months and deploying from the sunset to sunrise. To define the prospect of the energy saving, two variables were primarily evaluated: the greenhouse inside air temperature variation and thermal loads prompted by creating the optimum microclimate for tomato plant. Finally, an economic analysis is performed. The results show that 0° relative north (longer axis) is the optimal orientation for a gothic-arch greenhouse and that the thermal insulation blankets allow for reducing 17 % of the greenhouse heating needs under the climate conditions of Fez