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In order to ensure the flight safety of an aircraft and reduce the loss of humidity to the precision instruments and equipment in the aircraft, this study designs a small-size resonator antenna shape based on Radio Frequency Identification (RFID) technology and sensor principles. The resonator antenna makes use of the characteristics of the square ring and bent resonator and, at the same time, adopts the polyvinyl alcohol film with strong hygroscopic performance as the moisture-sensitive material. The equivalent resonant circuit of the sensor is constructed, and the parameters are optimized according to the principle of "coarse tuning of inductance parameters and fine tuning of capacitance parameters" to determine the optimal size. The relationship between the resonance frequency and the resonance response of humidity was investigated by the optimized model of the RFID resonator and polyvinyl alcohol (PVA). The simulation results show that as the relative humidity increases from 29.1 %RH to 90.9 %RH, the dielectric constant of the PVA film increases from 5.3 to 22 and the resonance frequency of the resonator decreases significantly from 4.74 to 4.12 GHz, with a total offset of 620 MHz, and the sensitivity is as high as 10.03 MHz/%RH. The results show that the designed sensor has a high sensitivity to humidity changes and a wide humidity detection range, providing an advanced solution for the detection and control of humidity inside aircraft. [ABSTRACT FROM AUTHOR]

In order to get the high temperature and humidity characteristics of key specifications for a power amplifier (PA), the degradation of the small-signal gain for a GaN class-AB dual-band PA under different temperature and humidity conditions is investigated experimentally. The experimental results show that the small-signal gain of the GaN class-AB dual-band PA will decrease under high temperature and humidity conditions. The main reasons for this degradation are discussed and analyzed in this paper. [ABSTRACT FROM AUTHOR]

The present paper investigates droplet and aerosol emission from the human respiratory function by numerical and experimental methods, which is analyzed at the worst-case scenario, a violent sneeze without a face covering. The research findings develop the understanding of airborne disease transmission relevant to COVID-19, its recent variants, and other airborne pathogens. A human sneeze is studied using a multiphase Computational Fluid Dynamics (CFD) model using detached eddy simulation coupled to the emission of droplets that break up, evaporate, and disperse. The model provides one of the first experimental benchmarks of CFD predictions of a human sneeze event. The experiments optically capture aerosols and droplets and are processed to provide spatiotemporal data to validate the CFD model. Under the context of large random uncertainty, the studies indicate the reasonable correlation of CFD prediction with experimental measurements using velocity profiles and exposure levels, indicating that the model captures the salient details relevant to pathogen dispersion. Second, the CFD model was extended to study the effect of relative humidity with respect to the Wells curve, providing additional insight into the complexities of evaporation and sedimentation characteristics in the context of turbulent and elevated humidity conditions associated with the sneeze. The CFD results indicated correlation with the Wells curve with additional insight into features, leading to non-conservative aspects associated with increased suspension time. These factors are found to be associated with the combination of evaporation and fluid-structure-induced suspension. This effect is studied for various ambient air humidity levels and peaks for lower humidity levels, indicating that the Wells curve may need a buffer in dry climates. Specifically, we find that the increased risk in dry climates may be up to 50% higher than would be predicted using the underlying assumptions in Wells' model. [ABSTRACT FROM AUTHOR]

The quantitative research on swelling properties of bentonite considering the influence of salt ions under the effect of hydrothermo-mechanical coupling is relatively weak. Based on a calculation model for the swelling characteristics of bentonite from a fractal perspective, this work proposes a novel coupled multifield control equation for unsaturated bentonite considering the influence of salt ions. The numericalization of the coupling control equation was completed by secondary development of a numerical analysis platform. The new theoretical model's dependability and validity were validated by comparing it to experimental data. The evolution of the related-field quantities under the multifield coupled effect in salt-bearing environments was obtained, and the effect of salt ion concentration was analyzed. The calculation showed that the temperature of bentonite changed periodically with changing ambient temperature. Temperature gradient induces migratory movement of water from high to low temperature regions. The hollow axisymmetric soil sample gradually saturated from outside to inside with increasing water injection rate at the outer cylindrical surface. The swelling pressure of bentonite will increase with an increase in water content, whereas the presence of salt ions weakened the swelling behavior. Temperature and relative humidity were less affected by salt ion concentration. [ABSTRACT FROM AUTHOR]

This paper reports a highly economical and accessible approach to generate different discrete relative humidity conditions in spatially separated wells of a modified multi-well plate for humidity assay of plant-pathogen interactions with good throughput. We demonstrated that a discrete humidity gradient could be formed within a few minutes and maintained over a period of a few days inside the device. The device consisted of a freeway channel in the top layer, multiple compartmented wells in the bottom layer, a water source, and a drying agent source. The combinational effects of evaporation, diffusion, and convection were synergized to establish the stable discrete humidity gradient. The device was employed to study visible and molecular disease phenotypes of soybean in responses to infection by Phytophthora sojae, an oomycete pathogen, under a set of humidity conditions, with two near-isogenic soybean lines, Williams and Williams 82, that differ for a Phytophthora resistance gene (Rps1-k). Our result showed that at 63% relative humidity, the transcript level of the defense gene GmPR1 was at minimum in the susceptible soybean line Williams and at maximal level in the resistant line Williams 82 following P. sojae CC5C infection. In addition, we investigated the effects of environmental temperature, dimensional and geometrical parameters, and other configurational factors on the ability of the device to generate miniature humidity environments. This work represents an exploratory effort to economically and efficiently manipulate humidity environments in a space-limited device and shows a great potential to facilitate humidity assay of plant seed germination and development, pathogen growth, and plant-pathogen interactions. Since the proposed device can be easily made, modified, and operated, it is believed that this present humidity manipulation technology will benefit many laboratories in the area of seed science, plant pathology, and plant-microbe biology, where humidity is an important factor that influences plant disease infection, establishment, and development. [ABSTRACT FROM AUTHOR]

This paper reports an experimental study of the contact electrification (CE) that happens when glass spheres of identical materials collide under different ambient relative humidity (RH) conditions. The experimental results indicate that the net charge on a sphere from a single collision is significantly altered by varying the RH level; the charge increases with increasing RH at low humidity, and then decreases at high RH conditions. The net charge reaches a maximum in the 20%-40% RH range. To explain the dependence of the CE on RH, we propose a model which yields predictions in agreement with the experimental data. The model also reveals how CE can be affected by temperature and surface absorption energy. [ABSTRACT FROM AUTHOR]

A reliable technique for evaluating a barrier film, which is a key component used to encapsulate flexible organic light-emitting diodes (OLEDs), is required to reliably appraise the lifetimes of such devices. The water vapor transmission rates (WVTR) is commonly used as an indication for a barrier film. In this paper, the variables affecting WVTR measurements were investigated because the results of such evaluations typically vary widely even at a level of 10-3 g m-2 day-1 at 40 °C and 90% relative humidity (RH). The reference films used for comparative measurements were prepared to eliminate the influence of the differences between individual barrier films. The measurement procedures were carefully investigated by using three WVTR measurement systems, which are based on different principles and different detectors. Consistency between the systems in terms of the WVTR was achieved at a level of 10-5 g m-2 day-1 at 40 °C and 90%RH. These results prove the reliability of not only our evaluation but also of these three systems, provided the measurements are performed correctly. The lag time was also analyzed to determine those factors that can affect the measurement time. It was found that the time required for a system to reach the adsorption-desorption equilibrium state can affect the measurement time. [ABSTRACT FROM AUTHOR]

We refer to the elongational testing of bread dough using a constant strain rate and specimens of varying initial diameter. Previously we found that 5 mm diameter specimens showed a much larger tensile stress for a given strain and strain rate than larger (20 mm diameter) specimens [Tanner et al., in Proceedings of the 5th International Symposium on Food Rheology and Structure, edited by P. Fischer, M. Pollard, and E. J. Windhab (ETH, Zurich, 2009), pp. 348-351]. It is important to understand this result because if it is true it is not possible to write a simple constitutive equation for the dough. In this paper, we examine the roles of ambient humidity and method of specimen preparation. The latter factor was seen to be crucial to obtaining consistent results in elongational testing of dough with different size specimens; it seems essential to limit pretest deformation to a Hencky strain of about 0.5 (extension ratio of about 1.6). Ambient humidity variations also affected the results, but the apparent shift with diameter was much smaller. [ABSTRACT FROM AUTHOR]

The effects of addition of ozone (O3) and humidity on oxygen (O2) bubbles during hydrogen peroxide (H2O2) generation by AC plasmas in the bubbles were investigated. The best H2O2 generation characteristics, with a generation rate and an efficiency of 161 mg/h and 1.74 g/kWh, respectively, were achieved when humidified O3 was used with ballast capacitors of 100 pF at 3 kHz. Zero-dimensional simulations of gas-phase reactions with different water vapor concentrations were performed to investigate the H2O2 generation reactions. It was confirmed that the use of humidified O3 contributed to hydrogen peroxide formation by enhancing OH radical generation via reactions involving O, H, and HO2 radicals. [ABSTRACT FROM AUTHOR]

The oxidation of uranium dioxide is a complicated process, depending on factors including humidity, temperature, and microstructure. To further determine the characteristics of this process, UO2 particles were allowed to age and agglomerate under 98% relative humidity at room temperature for 378 days. A focused ion beam (FIB) section of this agglomeration was then measured at the O K-edge, U N5-edge, and C K-edge using the scanning transmission x-ray microscope (STXM) at the Advanced Light Source. O K-edge and U N5-edge x-ray absorption measurements allowed for the elemental and chemical species mapping of the agglomerates and indicated the formation of schoepite at the submicrometer scale in specific locations. Non-negative matrix factorization was employed to elucidate the main components at the O K-edge, which were uranyl (schoepite) formed primarily at the interface of the sample with controlled atmosphere, a UO2-like bulk component present in the majority of the sample, and an oxygen species present at the surface of the FIB section, which is likely adsorbed water. STXM spectromicroscopy measurements at the U N5-edge measurements also confirmed the location of oxidized uranium. This analysis is a valuable insight into the formation of schoepite on UO2 and shows the sensitivity to and utility of STXM spectromicroscopy for uranium speciation. [ABSTRACT FROM AUTHOR]

Detailed knowledge of the species involved in the oxidation steps during combustion is of interest for technological applications. Using a formerly developed numerical model for a spark-plug discharge in dry air at atmospheric pressure, we studied here the influence of air humidity in the evolution of the densities of neutral and charged species and the gas temperature. The reduced electric field, electronic density, and temperature previously obtained from experimental measurements are parametrically introduced in the model. The effect of relative humidity with the values of 25%, 50%, 75%, and 100% is studied considering the water–air mixture formed by 63 species and coupled by 738 physical and chemical processes. The source term of the chemical reactions is calculated with the ZDPlaskin tool coupled to the numerical model. The analysis of the predominant pathways in the production and consumption of selected species is also carried out. Highly reactive species originated from the inclusion of water in the plasmochemical cycle reach relatively large density values and might play a significant role when considering an air–fuel mixture. [ABSTRACT FROM AUTHOR]

This work presents a monolithically integrated temperature and humidity sensor based on microelectromechanical systems technology. The temperature sensor working on the "bi-metallic" effect has the advantages of wide temperature range, high sensitivity, and fast detection. The humidity sensor has a polyimide parallel plate capacitive structure with the microporous array on the upper electrode designed for high sensitivity and fast response. Numerical analysis and COMSOL simulation showed that the temperature detection sensitivity is 0.2 mV/°C in the range of 193–393 K and humidity sensitivity is 0.405 pF/% relative humidity (RH) with the response time of 34 s in the humidity range of 0%–100% RH. The integrated temperature and humidity sensor has the advantages of small dimension, wide detection range, high precision, and fast response. [ABSTRACT FROM AUTHOR]

The effects of temperature and environmental moisture on the viscoelastic behavior of polyurethane foams were investigated both theoretically and experimentally. It was shown that the effect of the environmental parameters can be explained in terms of a variation of the free volume of the solid fraction of the foams, thus allowing the use of the superposition principle to predict their influence on the viscoelastic behavior of the materials. Dynamic mechanical analyses were performed to measure the dependence on frequency, temperature, and relative humidity of the complex modulus of two different polyurethane foams, differing in terms of their glass transition temperature. The time-temperature-humidity superposition principle was proved to be applicable for the tested materials. Next, the relaxation spectra and their dependence on the relative humidity were adopted to assess its effects on the large strain behavior of the foams. [ABSTRACT FROM AUTHOR]

The skin properties, structure, and performance can be influenced by many internal and external factors, such as age, gender, lifestyle, skin diseases, and a hydration level that can vary in relation to the environment. The aim of this work was to demonstrate the multifaceted influence of water on human skin through a combination of in vivo confocal Raman spectroscopy and images of volar-forearm skin captured with the laser scanning confocal microscopy. By means of this pilot study, the authors have both qualitatively and quantitatively studied the influence of changing the depth-dependent hydration level of the stratum corneum (SC) on the real contact area, surface roughness, and the dimensions of the primary lines and presented a new method for characterizing the contact area for different states of the skin. The hydration level of the skin and the thickness of the SC increased significantly due to uptake of moisture derived from liquid water or, to a much lesser extent, from humidity present in the environment. Hydrated skin was smoother and exhibited higher real contact area values. The highest rates of water uptake were observed for the upper few micrometers of skin and for short exposure times. [ABSTRACT FROM AUTHOR]

The oxidation properties of graphene oxide (GO) are systematically correlated with their chemical sensing properties. Based on an impedance analysis, the equivalent circuit models of the capacitive sensors are established, and it is demonstrated that capacitive operations are related to the degree of oxidation. This is also confirmed by X-ray diffraction and Raman analysis. Finally, highly sensitive stacked GO sensors are shown to detect humidity in capacitive mode, which can be useful in various applications requiring low power consumption. [ABSTRACT FROM AUTHOR]

We present a protocol for a facile orientation specific deposition of plate-like mesoporous SBA-15 silica particles onto a surface (mesopores oriented normal to surface). A drop of an aqueous dispersion of particles is placed on the surface and water vaporizes under controlled relative humidity. Three requirements are essential for uniform coverage: particle dispersion should not contain aggregates, a weak attraction between particles and surface is needed, and evaporation rate should be low. Aggregates are removed by stirring/sonication. Weak attraction is realized by introducing cationic groups to the surface. Insight into the mechanisms of the so-called coffee stain effect is also provided. [ABSTRACT FROM AUTHOR]

Surface charge of human hair has a significant effect on manageability, feel, and appearance. For this reason, controlling charge buildup to improve these factors is an important issue in the commercial hair care industry. In this study the surface potential of human hair is measured using the Kelvin probe method with an atomic force microscope. Samples are mounted in conductive silver paint, and a dc voltage is applied through the sample puck. The potential on the sample surface is then measured with a conductive tip. Caucasian virgin (undamaged), chemically damaged, and mechanically damaged hair samples are studied to determine the effect of damaging treatments on surface charge properties, and the different effects of chemical and mechanical damages on surface potential. Samples treated with commercial conditioner as well as those treated with an amino silicone conditioner are also studied to determine the effect of conditioner treatment. Similarly, the effect of surrounding environment is studied by varying the relative humidity experienced by the sample. Mechanisms for the given results are discussed and recommendations given. [ABSTRACT FROM AUTHOR]