Saturated Air Research Articles

Acoustics of wet porous media with evaporation/condensation

This paper investigates acoustic wave propagation in wet rigid-frame porous media accounting for evaporation and condensation. At equilibrium, the solid walls are covered by a thin water film, and water vapor in the air is at its temperature-dependent saturation pressure. Small acoustic perturbations cause water to vaporize or condense, which together with the reversibility of the phase change, lead to a linear problem where the usual local poro-acoustics physics is enriched with the (i) Clapeyron relation linking liquid-wall temperature, vapor pressure, and latent heat of vaporization, (ii) latent heat transfer in the solid frame, (iii) diffusion equation for water vapor in air, and (iv) water vapor's equation of state. The equilibrium temperature highly influences the vapor concentration and the physical parameters of saturated moist air. Using the two-scale asymptotic homogenization method, it is shown that the dynamic permeability is determined similarly to classical porous media, while the effective compressibility is modified by evaporation/condensation and the equilibrium temperature. This modification is influenced by vapor mass and heat flows associated with phase changes through a local fully coupled heat transfer and water vapor diffusion problem, with specific boundary conditions at the gas–water interface. The analysis identifies dimensionless parameters and characteristic frequencies defining the upscaled model's features. Depending on equilibrium temperature, the theory qualitatively and quantitatively determines the characteristics of acoustic waves propagating through the media. The results are illustrated and discussed with analytically developed models.

Comparison Study Between Inherited and Biogenic Calcium Carbonate Formation on The Surface Roots of Eucalyptus Trees Using X-Ray Technique and Field Observations

Background: This study aims to explain the mechanism of formation of calcite and it's to shed light on the synthetic carbonate crystallization on the surface of roots due to this mechanism is poorly understood and highly controversial. It is accepted that calcite formed originally from parent rocks and not in soils. Method: The origin of calcite in calcareous soil, in Aldiwaniya city, Iraq was investigated, by selecting two soil samples, one from the contact zone with root surface and the other sample from bulk soil and out of the root system. Results: X-ray diffraction showed that the calcite has two types, first one is well crystallized and ordered, with only minor deviations in lattice unit cell parameters relative to typical calcite. The clay-sized calcite (active calcite) is enriched in A and C-horizons relative to biogenic calcite and this mineral exist in larger size separates, and it's clearly appears in the shape of white crystals around eucalyptus root surfaces as shown in graphs. The results of X-ray showed that the appearance of smectite mineral which was diagnosed by the peak 14.21 A° in air dry magnesium-saturated treatment which expanded to 16.28 A° when saturated with ethylene glycol, where clarity of peak was increased, Also, the results showed that the appearance of peak 14.21 A° in magnesium saturation air dried, as a shoulder on the peak of the mica (10.14 A°). Conclusion: In general, calcite minerals have characteristic x-ray diffraction peaks at the following angles: 29.5, 31.7, 34.5, 35.7, 47.3, 56.4, and 63.4 degrees.

Cloud-Edge Motion by a Ducted Gravity Wave

Abstract The reflection of a wave at a fluid interface is fundamental to the atmospheric wave duct. As latent heating distinguishes the buoyancy response between cloudy and clear air, cloud edges can serve as a ducting interface for gravity waves. However, advection of the thermodynamic conditions by the ducted wave itself can cause evaporation or condensation, where the motion of cloud edges results from shrinking or enlarging regions of saturated air. For an idealized ducted wave mode trapped by a cloud layer, a linear Boussinesq analysis shows that its vertical motions produce a sinusoidal corrugation of the cloud edge that travels with the wave. When thermodynamic conditions are continuously varying, the cloud edge propagates as a moving onset of phase change and not as a material interface. Using this Boussinesq solution to initialize the full-physics Cloud Model 1 (CM1), the simulation confirms the amplitude and speed of the cloud-edge wave. In a comparison of simulations for domains of decreasing height, convergence to the Boussinesq ducted wave can be quantitatively established. This demonstration suggests a theory-based convergence benchmark for the motion of a cloud edge by phase change. Significance Statement Waves in the atmosphere can cause evaporation or condensation that results in changes to the shape of an individual cloud. A standard theory for airflow is extended to include the motion of the edges of a cloud. An example wave cloud as approximated by this theory is shown to be reproduced, with high accuracy, in a computer weather forecast model. The quantitative verification of this basic theory for clouds represents a new opportunity for exploring how wave interactions may be involved in the complex processes that shape the clouds that are an important component in our weather and climate systems.

Frontal effects on the rapid formation of a deep layer of marine fog and cloud in the NW Atlantic

AbstractRapid formation of a deep layer of fog and clouds extending to a height of 2 km was observed over Sable Island off Nova Scotia on 13–14 July 2019. This fog and cloud event was dominantly caused by the rapid intrusion of a trough from a cyclone over NE Canada. The trough quickly moved from SW–W to E–NE and encroached on the coastal waters of Nova Scotia. Due to the warm front in the trough, the air temperature increased up to 4 km in height with increased stability, while the sea‐level pressure at Sable Island dropped by 11 hPa within 12 hours. The moderate to strong winds turned counterclockwise from the N to the SE, converging with the SE winds maintained by the ridge located to the east. There was no indication of an advection‐type fog mechanism because the surface air temperature was not adjusted to the colder sea‐surface temperature that could have resulted in saturation of the surface air. The leading portion of a massive cloud band in the trough passing over Sable Island included precipitation before fog formation. The rain that evaporated in the unsaturated and warm subcloud layer effectively reduced the air temperature and significantly increased the wet‐bulb temperature in this layer. The cloud extended into the moist subcloud layer, while fog formed at 1400 UTC 13 July and lasted until 2327 UTC 13 July (with two brief periods of mist lasting less than two hours). The development of this deep layer of fog and cloud in the NW Atlantic was caused by evolving synoptic conditions through the simultaneous effects of a rapid trough intrusion over coastal waters with a massive cloud band, induced precipitation causing cloud deepening into the subcloud layer, and surface wind convergence forcing vertical mixing in a stable marine boundary layer.

High potency of application on an open direct-contact thermal storage using humid air

To reuse low-temperature wasted heat as a thermal resource for high temperature, a direct-contact adsorption thermal storage was focused using humid air and zeolite 13X particles as the working fluid and adsorbent, respectively. Only a few previous studies have chosen the working fluid in gaseous form because it is unavailable for latent heat in generating heat sources. Recovering waste heat in humid air to generate hotter steam is unique and becomes an originality of our present work. The time required to regenerate zeolite particles and the maximum temperature of the generated steam were investigated assuming a warm-up device for a vehicle. The time required to regenerate zeolite was investigated by changing the dew point, temperature, and superficial velocity of the inlet humid air. It was mainly affected by the temperature of the inlet air. The absorbent was regenerated within 30 min when the humid air preheated to 200 °C was supplied. On the other hand, the maximum steam temperature was investigated by changing the superficial velocity and temperature of saturated inlet humid air. As one of the significant and novel finding in this work, the steam of >200 °C was obtained as a high-temperature heat source even with saturated humid air unavailable latent heat. Moreover, as theoretical knowledge, it was revealed that the maximum temperature of the heat source can be estimated by the relationship between the heat balance on the packed bed and adsorption equilibrium.

Evaluating low pressure storage for prolonging the postharvest life of blueberries

Low pressure storage (LPS) is a postharvest technology that has shown the potential to extend the storage life of various horticultural commodities. LPS addresses core postharvest challenges, such as desiccation, decay and senescence by creating an environment that maintains fully saturated air (i.e., high relative humidity) and ultra-low oxygen (ULO) conditions that can reduce respiration rates and suppress fungal growth. In this study, LPS chambers were evaluated for their ability to extend the storage life of blueberries (Vaccinium corymbosum L., cv. ‘Draper’), compared to regular atmosphere (RA), across four different storage locations in the Pacific Northwest, USA. In three of the four locations, blueberries were field picked and loaded by hand, while at one location, fruit was loaded through mechanical harvesters. Following two weeks of storage, LPS chambers reduced blueberry respiration rates by 47 % from initial to lowest point, on average. Vacuum chambers filled with machine harvested fruit exhibited respiration rates 28 % higher than chambers with hand harvested fruit, although still sustained rates lower than at the initial loading (i.e., harvest). After five to eight weeks of storage, LPS chambers sustained nearly no weight loss, while fruit stored under RA conditions demonstrated weight loss between 2 and 7 % in the same period. LPS fruit was firmer, exhibited less incidence of superficial mold and fungal decay and better maintained titratable acidity than RA fruit. LPS chambers, when field loaded by hand, demonstrate significant potential in maintaining the at-harvest quality and condition of blueberries for up to eight weeks postharvest. Under these conditions, LPS can extend the storability of blueberries for eight weeks or more. Further investigation is required to determine the compatibility of extended LPS on machine harvested blueberries and with other commercially relevant cultivars.

Intensive Radiosonde Observations of Environmental Conditions on the Development of a Mesoscale Convective System in the Baiu Frontal Zone

AbstractMesoscale convective systems (MCSs) that occur in the Baiu frontal zone (BFZ) can cause devastating flash floods during early summer in Japan; however, the environmental conditions necessary for their development require further investigation. High‐frequency atmospheric soundings, conducted using multiple marine vessels in the East China Sea on 19 June 2022, captured the detailed environmental conditions pertaining to the development of an MCS within the BFZ. The MCS, which developed rapidly without any remarkable preceding synoptic or mesoscale disturbance in the mid‐ or upper troposphere, caused intense precipitation exceeding 80 mm/hr. The MCS persisted for approximately 6 hr, and it intensified when the influx of nearly saturated air near the sea surface toward a weak surface front overlapped with the influx of free‐tropospheric moist air. The influx of nearly saturated air near the sea surface ensured conditional instability within the lower troposphere. The influx of moist air in the free troposphere contributed to the near‐saturation conditions above the boundary layer, a feature inherent to the BFZ, and played an important role in minimizing the reduction in the buoyancy of air parcels. The results of this study indicate that a better forecast of the horizontal distribution of free tropospheric moist air is beneficial for limiting the potential area of genesis of MCS in the BFZ, and a more comprehensive understanding of the vertical variations in moisture transport contributes to an improved forecast skill for MCS in the BFZ.

Investigation of thermodynamic process in a humidifier of humidification–dehumidification system based on a computational fluid dynamics model

Humidification–dehumidification is well-suited for solar-powered operation. Packed bed humidifier is an essential system component for water evaporation. Computational fluid dynamics (CFD) simulation of the packed bed humidifier is a challenging multiscale task. The simultaneous capture of micro flow properties and macro transfer performance by existing CFD models is inadequate. This paper presents a novel CFD model for a structured packed bed humidifier. The Eulerian method is applied to the multiphase flow and several simplified models are proposed to evaluate the influence of the microstructure on the transfer properties. The model can predict the overall transfer performance and partially reflect the micro flow characteristics. It is found that the air temperature increases rapidly when the packing height is < 0.3 m, while the liquid temperature decreases rapidly when the height is > 1.65 m or <0.45 m. Under different conditions, the outlet relative humidity of the air is all between 95 % and 99 %. The maximum evaluation error of gained output ratio of the humidification–dehumidification system can reach 10 % under the saturated air assumption. With a maximum of 10.85 % and a minimum of 3.46 %, the proportion of sensible heat transfer in the total energy transfer decreases with the packing height.

Homogenization of the Color of Beech Sapwood and False Heartwood by the Steaming Process

This work presents the results of the homogenization of the color of sapwood and false heartwood Fagus sylvatica L. into a uniform color shade due to the influence of the temperature of saturated moist air and saturated water steam in individual steaming modes. The results of analyses of the influence of temperature within 24 h point out the different changes in the color of the sapwood and the wood of the false heartwood when the uniform color of the beech wood is achieved by the steaming process. By steaming beech wood with a false heartwood saturated with moist air at a temperature of tI = 95 °C during τ = 24 h, the color of the sapwood does not merge with the color of the wood of the false heartwood. The sapwood darkens and, on the other hand, the wood of the false heartwood slightly lightens, while the significant color contrast is removed, but the color homogenization in the individual zones does not occur. The unification of the colors in individual zones occurs during the steaming process at a temperature of saturated water steam tII ≈ 105 °C in 18 h, where the resulting brown color is identified in the color space CIE L*a*b* by the values of the lightness L* = 61.3 ± 2.2 and of the red color a* = 12.4 ± 1.3 and yellow color b* = 19.5 ± 1.4. The most pronounced homogenization of the color occurs through the steaming process at a temperature of saturated water steam tIII ≈ 120 °C, where the wood acquires a uniform dark brown–gray color in a time of τ ≈ 9 h steaming. The coordinates of the color-homogenized steamed beech wood are L* = 55.9 ± 1.9, a* = 12.3 ± 1.2, and b* = 19.6 ± 1.3. The unification of the colors by the steaming process is achieved by darkening both the sapwood and the wood of the false heartwood. In the overall color homogenization, the sapwood and the wood of the false heartwood do not participate equally in the steaming process. While the total color difference between the sapwood and a color homogenized state is quantified by the value ∆EtI* = 8, ∆EtIII* = 22.7, the total color difference in the wood with a false heartwood is only ∆EtI* = 1.9, ∆EtIII* = 11.8.

Investigation on Natural Convection in a Square Porous Cavity with an Open Side

Natural convection in a porous, rectangular hollow full of saturated air was investigated numerically in the current study. The bottom side was warmed with a continuous heat flux, the right side's temperature was kept at (Tc), the left wall was opened to the surroundings, and the top side was insulated. The pertinent filled-out research parameters in the current experiment were four heat flux values (1500, 3000, 4500, and 6000 W/m²) and three Darcy’s numbers (Da1=4.025×10-10, Da2=4.025×10-8, Da3=4.025×10-6). COMSOL Multiphysics 5.5a, using finite elements and a relying Brinkman-Darcy extended model, was employed to resolve government equations. Local thermal balance simulation was assumed in this solution. Energy transfer and momentum were studied using isotherms and streamlines. The findings appeared that the flow velocity improved with the rising Darcy number, especially in the case of Da3, as well as increasing the average Nusselt number about 110 % and 45% for Da3 and Da2 compared with Da1. Additionally, the increase in heat flux will increase the heat transfer, especially with Da3.

Atmospheric air freshwater using TPMS compact heat exchangers

The technology of extracting freshwater from atmospheric air is currently accessible in tropical regions and is experiencing substantial growth in areas where freshwater scarcity is prevalent. Moreover, the water-cooling towers in power plants and district cooling chillers produce saturated air, which serves as a significant supply of humid air and consequently freshwater. Dehumidification is the necessary procedure for extracting water vapor from moist and saturated air in order to generate water. An efficient heat exchanger with a high ratio of surface area to volume is necessary to enhance the production of freshwater by condensing the water vapor present in the air. Triply periodic minimum surface (TPMS) structures possess intricate geometries, resulting in a high ratio of surface area to volume and intense turbulence. Consequently, these structures have exceptional heat transmission capabilities. The internal network structure of the TPMS enables the formation of a consistent layer of freshwater by direct interaction with humid airflow, resulting in a continuous flow. The objective of this study was to examine the structural architectures of TMPS that maximize the generation of freshwater from moist air under various humidity and flow conditions. This was achieved by employing accurate 3D computational fluid dynamics (CFD) models. The purpose of developing these models is to analyze the performance of the Gyroid-Solid TPMS structure and compare it to a vertical flat plate with the same surface area. Furthermore, the study examines the freshwater production efficiency of various TPMS designs (Gyroid-Solid, Gyroid-Sheet, and Diamond-Solid) with same porosity but varying levels of humidity in the air. The findings indicate that the Gyroid-Solid structure enhances the condensation flow rate by a threefold factor in comparison to the flat plate across different levels of humidity in the air. Furthermore, the findings indicated that Diamond-Solid exhibited superior performance when subjected to low airflow Reynolds numbers, whereas at high Reynolds numbers The Gyroid-Sheet exhibits the highest level of condensation among the three solid structures, surpassing the Diamond-Solid by 25% and the Gyroid-Solid by 65 %. The findings demonstrated a notable increase in the production of freshwater through the utilization of TPMS structures, thereby deepening our understanding of the crucial influence of geometry on the condensation process. Empirical formulae have been formulated to calculate the Nusselt number of atmospheric air for TPMS heat exchangers, taking into account various design and operational factors.

Low frequency sounds from tornadoes

It has been well established that tornadic storms can generate infrasound (i.e., sound at frequencies below human hearing) signals, but the mechanism of sound generation is still a mystery. There is speculation that these infrasound signals have the potential to serve as an alternative method for alerting and/or tracking of life-threatening tornadoes. Yet, until the mechanism for infrasound generation is understood, it remains a possibility that the infrasound signals are present due to other storm effects and would be improper to use for tornado warning or tracking. One possible explanation for the infrasound signals is an amplification of turbulent fluctuations due to latent heat production. This presentation will detail laboratory efforts to isolate noise production from turbulent structures with and without latent heat production due to condensation of water in saturated warm air. [This work was supported by the Gordon and Betty Moore Foundation, grant DOI 10.37807/gbmf11559.]

Influence of temperature perturbation on moisture dynamics

We analyzed the perturbation effect of temperature on the moisture content in the atmosphere [], considering the saturation phenomenon. The air parcels of a saturated atmosphere are made of dry air, vapor, cloud, and rain water that flow on a rotating Earth, with a temperature perturbations induced at 9°1′48″ N, 38°44′24″E and 6.324 km above the Earth’s surface. The fundamental atmospheric parameter of this saturated moist air was treated as temperature-dependent, and the pressure force exerted on it by the precipitation and cloud water is not considered in the numerical computation. In this proposed research, the initial value of wind speed along zonal, meridional, and vertical directions varies with elevation, and the interaction of the atmosphere with the Earth’s surface is not neglected. The result of the investigation revealed that a single tropospheric disturbance of an atmospheric variable is a major factor in the spread of different long period waves patterns (350 hours) and this atmospheric oscillations play a crucial role in transferring energy, momentum, and mass across different parts of the atmosphere, impacting global climate systems.

Small-Scale Diffusion Dryer on an Optical Particle Counter for High-Humidity Aerosol Measurements with an Uncrewed Aircraft System

Abstract The negative effects of relative humidity to measurements of particulate matter (PM) due to hygroscopic growth are often not inherently handled by low-cost optical particle counters (OPCs). This study presents a new approach in constructing a miniaturized diffusion dryer, for use with an OPC mounted on an uncrewed aircraft system (UAS), namely, the DJI S900 (weight of 7.5 kg and flight endurance of 20 min) for short-term measurements under humid conditions. In this work, an OPC of type N3 (Alphasense) was employed alongside the dryer, with experiments both in the laboratory and outdoors. Evaluation of the dryer’s performance in a fog tank showed effective drying from almost saturated air to 41% relative humidity for 35 min, which is longer than the endurance of the UAS, and therefore sufficient. Changes in the flow rate through the OPC-N3 with the dryer showed a 17% reduction compared to an absent dryer, but the measured PM values remained unaffected. Airborne measurements were taken from four hovering flights near a governmental air pollution station (Mannheim-Nord, Germany) under humid conditions (88%–93%) where the system gave agreeable concentrations when the dryer was in place, but significantly overestimated all PM types without it. At a rural area near the Boundary Layer Field Site Falkenberg (Lindenberg, Germany), operated by the German Meteorological Service (DWD), vertical profiles inside a low-altitude cloud showed sharp increase in concentrations when the UAS entered the cloud layer, demonstrating its capability to accurately detect the layer base.

In Situ Generation of H2O2 over MoOx Decorated on Cu2O@CuO Core-Shell Particle Nanoarchitectonics for Boosting Photocatalytic Oxidative Desulfurization.

Photocatalytic oxidation desulfurization (PODS) has emerged as a promising, ecofriendly alternative to traditional, energy-intensive fuel desulfurization methods. Nevertheless, its progress is still hindered due to the slow sulfide oxidation kinetics in the current catalytic systems. Herein, we present a MoOx decorated on a Cu2O@CuO core-shell catalyst, which enables a new, efficient PODS pathway by in situ generation of hydrogen peroxide (H2O2) with saturated moist air as the oxidant source. The photocatalyst delivers remarkable specific activity in oxidizing dibenzothiophene (DBT), achieving a superior rate of 7.8 mmol g-1 h-1, while maintaining a consistent performance across consecutive reuses. Experimental investigations reveal that H2O2 is produced through the two-electron oxygen reduction reaction (ORR), and both H2O2 and the hydroxyl radicals (•OH) generated from it act as the primary reactive species responsible for sulfide oxidation. Importantly, our catalyst accomplishes complete PODS of real diesel fuel, underscoring an appealing industrial prospect for our photocatalyst.

Model-free optimal robust tracking control for the joint actuated by pneumatic artificial muscles with saturated air pressure input

At present, positioning and tracking the joint angle of the PAM-actuated system is still a challenging issue, due to the inherent hysteresis, high nonlinearities, and time-varying characteristics. Considering the problem of uncertain parameters, external disturbance, and saturated input, a model-free optimal robust tracking control scheme is proposed for the PAMs system in this paper. Also, a nonquadratic cost function is introduced to address the saturation air pressure input. Moreover, an integral reinforcement learning(IRL) algorithm is developed to solve the H∞ tracking Hamilton–Jacobi–Isaacs(HJI) equation. And the IRL algorithm is implemented on a critic–actor-disturbance neural network (NN) structure. The presented control scheme avoids the complete system dynamic and simultaneously compensates for the uncertain parameters, and external disturbance. Then, the effectiveness of the optimal robust tracking controller is verified via computational simulation and keeps the system stable. In addition, the tracking experiment is implemented on a hardware platform, indicating that the presented approach achieves satisfactory tracking performance.

Validation and traceability of miniaturized multi-parameter cluster radiosondes used for atmospheric observations

In this work we designed and developed a cluster of light expendable radiosondes that can float passively inside warm clouds to study their micro-physical processes. This involves the tracking of both saturated and unsaturated turbulent air parcels. The aim of this new kind of observation system is to obtain Lagrangian statistics of the intense turbulence inside warm clouds and of the lower intensity turbulence that is typical of the air surrounding such clouds. Each radiosonde in a cluster includes an electronic board, which is mounted onto a small, biodegradable balloon filled with a mixture of helium and air. The cluster is able to float inside clouds for a few hours and to measure air temperature, pressure, humidity and the associated position, velocity, acceleration and magnetic field readings of each radiosonde along their trajectory.

Enterobacteriaceae counts influenced by different scalding techniques in broiler processing

In the highly automated processing in broiler abattoirs, some process steps reduce the bacterial counts and inactivate or remove pathogens, while others can lead to an increase. The present study compared the reduction of Enterobacteriaceae counts (EBCs) on breast skin samples in 3 broiler abattoirs using different scalding techniques: (A) conventional immersion scalding (360 s), (B) conventional immersion scalding with thermal treatment of the water (204 s), and (C) the AeroScalder® using hot, humid, saturated air as the scalding medium (360 s in air). In 3 commercial broiler abattoirs in Germany and The Netherlands, a total of 320 breast skin samples per abattoir (before and after scalding, after plucking, before and after chilling) and water samples from the scalders were taken and examined for EBC. After scalding, a significant EBC reduction by 0.7 log was determined only for the conventional immersion scalder (Abbatoir A); the reductions of the other 2 scalders were 0.1 log (Abattoir B) and 0.2 log (Abattoir C) and not statistically significant. The EBCs after scalding differed by up to 0.5 log cfu/g when the 3 scalders were compared, and these counts can be seen as similar. For all 3 abattoirs, the largest EBC reductions (p < 0.001) of 2.8 to 3.6 logs were found after plucking. Compared to the immersion scalders, EBCs in water samples were lowest in those taken from the AeroScalder®. Hence, we conclude that the conventional immersion scalders and the AeroScalder® reduced EBCs in a comparable manner. However, the greatest reductions in EBCs were seen after the plucking steps in the studied abattoirs, not after the scalding as such.

Effects of short-term air pollution exposure on symptoms development in the course of idiopathic pulmonary fibrosis

ABSTRACT Background Lately a potential detrimental effect of air pollution to idiopathic pulmonary fibrosis emerged. We aimed to assess the effects of short-term air pollution exposure to the clinical course of IPF. Research design and methods IPF patients were followed intensively for four nonconsecutive study periods between 13 July 2020 and 5 September 2021. Short-term exposure to O3, NO2 and PM10 concentrations was estimated using spatio-temporal land use regression models. Associations among symptoms, lung function, oxygen saturation, and short-term personal air pollutant exposure were assessed through multiple mixed effects logistic regression models. Results Data for up to 24 IPF patients (mean age: 72.2 ± 7.6 years) were analyzed. We detected positive significant associations between cough and a 10 μg/m3 increase in same day mean level of NO2 (OR = 1.59, 95%CI: 1.00–2.53), PM10 (OR = 2.42, 95%CI: 1.54–3.79), and O3 (OR = 1.63, 95%CI: 1.14–2.32). A 10 μg/m3 increase in same day mean level of NO2 was also associated with the risk of appearance of wheezing (OR = 3.01, 95%CI: 1.00–9.04), while exposure to O3 was associated with common cold (OR = 6.30, 95%CI: 3.59–11.07). No significant associations were detected between short-term exposure to air pollutants and forced vital capacity or saturation of oxygen. Conclusions Short-term exposure to increased concentrations of air pollutants is an independent risk factor for IPF symptoms' aggravation.

Study on the Unified Mechanical Properties of Ili Undisturbed Loess under the Influence of Soluble Salt

Through three stress path tests of unsaturated Ili undisturbed loess, the effect of soluble salt content on the deformation of net mean stress, suction, and deviated stress were investigated. The mechanical properties of the normalized compression curve, soil water characteristic curve and critical state line were revealed. The test results indicate that: in the isotropic compression test, the normal compression curves controlling different suctions can be characterized by using the initial void ratio and the yield net mean stress, and can be described as a two-parameter exponential function. In the triaxial shrinkage test, the soil water characteristic curves controlling vary net mean stresses are dimensionless by using saturated moisture and air entry value, and the normalization formula can be characterized by a single parameter exponential function. In the consolidation shear test, the corresponding effective net mean stress is calculated by suction and saturation. The critical state lines under the unsaturated condition controlling vary suctions can be described as the critical state line under the saturated condition on the plane of effective net mean stress and deviator stress. When the effective net mean stress is constant, the critical state lines under the unsaturated condition can be characterized by the degree of gas saturation and the ratio of unsaturated void ratio to saturated void ratio. The research will offer reference pointing at the regulation and utilization of water and salt in the loess region of Central Asia, so as to better guarantee the sustainable development of saline-alkali land project construction.