Humidity Measurements Research Articles

Evaluation of a Temperature/Humidity Data Logger for the Usage in Cattle Barns

Climate change is a worldwide problem that is manifested in livestock farming with a decrease in animal health and welfare and economic losses due to heat stress. Therefore, a precise and continuous recording of the barn climate is essential to be able to implement actions at a certain threshold. The aim of this study was to evaluate a logger for temperature and humidity (Kestrel Drop D2) marketed for on-farm use in comparison to various other temperature/humidity data loggers under field conditions. Four different sensors were used and placed in different settings in cattle barns to correlate temperature and humidity measurements. Data were recorded for over a year in total. The data were very highly correlated. Furthermore, the area under the curve for the evaluated logger in comparison to the other ones was 0.99 to 1.0, using a temperature–humidity index cut-off of 72, often set to define heat stress. In conclusion, the evaluated logger performed equally well as the other used devices. For on-farm use, it is suitable.

Simultaneous monitoring of humidity and temperature by polarization volume gratings utilizing responsive cholesteric liquid crystals

Optical sensing devices are utilized for noncontact operation in harsh environments due to their advantage of local separation between the measurement and detector systems. Cholesteric liquid crystals (CLCs) with vivid structural colors are integrated into optical sensors, attracting significant interest for naked-eye detection. To enable vision-based, real-time remote monitoring, we propose a cost-effective method to convert the stimuli-responsive reflection change of CLCs into recordable diffraction patterns using polarization volume gratings (PVGs). This enables real-time remote readout of environmental parameters. PVGs are constructed through holographic polarization interference and photoalignment technologies. The diffraction efficiency of PVGs varies with relative humidity (RH). To improve sensing accuracy and extend the monitoring range of RH, we employ two methods: an orthogonal grating structure and dual-wavelength detection optical path. In addition, we demonstrate the simultaneous measurement of humidity and temperature by cascading independently responding PVGs. We believe that this work will provide a broader perspective and expand the application of light dimensions in LC-based optical sensing.

Interfacially Fabricated Covalent Organic Framework Membranes for Film-Based Fluorescence Humidity Sensors and Moisture Driven Actuators.

Rapid, on-site measurement of ppm-level humidity in real time remains a challenge. In this work, we fabricated a few micrometer thick, β-ketoenamine-linked covalent organic framework (COF) membrane via interfacially confined condensation of 1,3,5-tris-(4-aminophenyl)triazine (TTA) with 1,3,5-tri-formylphloroglucinol (TP). Based on the super-sensitive and reversible response of the COF membrane to water vapor, we developed a high-performance film-based fluorescence humidity sensor, depicting unprecedented detection limit of 0.005 ppm, fast response/recovery (2.2 s/2.0 s), and a detection range from 0.005 to 100 ppm. Remarkably, more than 7,000-time continuous tests showed no observable change in the performance of the sensor. The applicability of the sensor was verified by on-site and real-time monitoring of humidity in a glovebox. The superior performance of the sensor was ascribed to the highly porous structure and unique affinity of the COF membrane to water molecules as they enable fast mass transfer and efficient utilization of the water binding sites. Moreover, based on the remarkable moisture driven deformation of the COF membrane and its composition with the known polyimide films, some conceptual actuators were created. This study brings new ideas to the design of ultra-sensitive film-based fluorescent sensors (FFSs) and high-performance actuators.

Study on a Multi-Array Based Integrated Temperature and Humidity Measurement System for In Cabin Sensing

Study on a Multi-Array Based Integrated Temperature and Humidity Measurement System for In Cabin Sensing

Microclimate of Brown Bear (Ursus arctos L.) Dens and Denning Area

The aim of this study was to determine the microclimate of brown bear dens depending on their size, their status (active or inactive), and the location of the den. The study included five dens of different sizes and locations in the Velebit Mountains, in the Dinaric Alps. The measurements of air temperature (°C) and relative humidity (%) in dens and the forest stands were carried out over 182 days. The absolute minimum air temperature in inactive dens was between −2.88 °C and −0.38 °C and belonged to the dens with shorter tunnels and without chambers. The exception was inactive den 1, which was situated in a thermophilic forest. No negative absolute minimum air temperatures were recorded in active dens. The absolute minimum air temperatures in the forest stands were lower than in the dens. The relative humidity was significantly higher in all dens than in the forest stands. Dens with a large entrance opening and a short tunnel were strongly influenced by the local microclimate of the forest stand. The greatest temperature difference (den–forest) was between elongated dens with chambers and the associated forest stand, while the smallest temperature differences occurred in dens with a short tunnel, without a chamber, and at the northern exposure. The greatest differences in relative humidity (den–forest) were found in dens with chambers. The den temperatures correlated with the air temperatures in the forest stands.

Indoor Environment in Kindergartens Located in the North of Portugal: Evaluation of Thermal Comfort and Carbon Dioxide Concentration

Adequate school buildings are essential for the development of children, young people, and adolescents, as they must provide conditions that support their well-being and health. A healthy and comfortable indoor environment is critical for students’ performance in the learning process. This study aims to evaluate the indoor environment in kindergartens located in northern Portugal, with a primary focus on thermal comfort and indoor air quality. To achieve this, five buildings with varying construction characteristics were monitored, with temperature and relative humidity measurements taken in classrooms of different orientations over time. Additionally, the outdoor climate was also monitored. Based on the collected data, thermal comfort was evaluated using the adaptive model defined by the European standard EN 16798. Continuous monitoring of carbon dioxide concentration was also conducted in three of these buildings. The results reveal significant heterogeneity among the buildings, demonstrating the influence of construction characteristics on the interior thermal conditions. The recorded temperatures ranged from 10 °C to 27 °C, highlighting a substantial variability in performance across the different buildings. Particularly, the orientation and size of glazed openings, together with the lack of thermal insulation in the building envelope, especially in the roof, were found to have an important impact on the thermal comfort of the occupants. Furthermore, a relationship was observed between the daily maximum carbon dioxide concentration and the outdoor temperature, as a result of users’ efforts to minimize uncontrolled air infiltration, by limiting the opening of doors and windows, with consequences in the air exchange between the interior and exterior.

Comparison of Actual Deformations of Historic Wooden Structures with Values Obtained from Static Calculations

In historic wooden structures, deformations can be influenced by factors that are negligible within the first 50 years of the building's existence. In attics where the roof covering is made of metal sheets, the air and structural elements heat up during the day and cool down rapidly at night. This phenomenon, over a long period, can cause micro-cracks and surface material degradation. For the study, historic buildings meeting the criteria for service class II according to PN-EN 1995-1-1 were selected. Measurements of deflections, humidity, and modulus of elasticity of the wood were conducted. The actual deflections of the examined structures were found to be 28% to 37% higher than those obtained from numerical calculations, indicating ongoing rheological processes in the wooden structures.

Energy retrofits: Factors affecting a just transition to better indoor air quality

In comparison with other European countries, Ireland has a disproportionately high number of poorly performing energy-inefficient buildings. Consequently, Ireland has one of the most ambitious energy retrofit programmes in Europe. The aim of this study was to evaluate the impact of deep energy renovation measures i.e. (replacement of heating system and upgrade to building envelope) on indoor air quality, thermal comfort and ventilation in a sample of primarily social housing in Ireland. A mixed methods approach including measurement of indoor air quality and a thermal comfort questionnaire survey was employed. Indoor concentration measurements of PM2.5, carbon dioxide, formaldehyde, and radon along with measurements of air temperature and relative humidity were made (N=14). Occupants (n=56) completed a thermal comfort questionnaire survey pre- and post-retrofit. Data collection ran from autumn 2020 until autumn 2023.Thermal comfort improved post-retrofit along with occupant satisfaction with the indoor thermal environment and heating-systems. Post-retrofit, higher bedroom CO2, and higher PM2.5 concentrations were recorded in both living areas and bedrooms. Occupant behaviours e.g. blocking wall vents were significant predictors of poorer ventilation while smoking indoors was related to higher concentrations of PM2.5. In general, homes that had mechanical ventilation systems installed were better ventilated. Underventilation, as indicated by visible condensation or mould was observed in half of the social homes surveyed and reported by questionnaire respondents (26 %). Tailored communications to occupants regarding the important role of ventilation and indoor air quality is required as part of retrofit to optimise impacts on IEQ.

An Empirical Parameterization of the Subgrid‐Scale Distribution of Water Vapor in the UTLS for Atmospheric General Circulation Models

AbstractTemperature and water vapor are known to fluctuate on multiple scales. In this study 27 years of airborne measurements of temperature and relative humidity from In‐service Aircraft for a Global Observing System (IAGOS) are used to parameterize the distribution of water vapor in the upper troposphere and lower stratosphere. The parameterization is designed to simulate water vapor fluctuations within gridboxes of atmospheric general circulation models (AGCMs) with typical size of a few tens to a few hundred kilometers. The distributions currently used in such models are often not supported by observations at high altitude. More sophisticated distributions are key to represent ice supersaturation, a physical phenomenon that plays a major role in the formation of natural cirrus and contrail cirrus. Here the observed distributions are fitted with a beta law whose parameters are adjusted from the gridbox mean variables. More specifically the standard deviation and skewness of the distributions are expressed as empirical functions of the average temperature and specific humidity, two typical prognostic variables of AGCMs. Thus, the distribution of water vapor is fully parameterized for a use in these models. The new parameterization reproduces the observed distributions with a determination coefficient always greater than 0.917 and with a mean value of 0.997. The parameterization is robust to a selection of various geographical subsets of data and to gridbox sizes varying between 25 and 300 km.

A New NDSA (Normalized Differential Spectral Attenuation) Measurement Campaign for Estimating Water Vapor Along a Radio Link

The Normalized Differential Spectral Attenuation (NDSA) technique was proposed years ago as an active method for measuring integrated water vapor (IWV) along a Ku/K-band radio link immersed (totally or partially) in the troposphere. The approach is of the active kind, as it relies on the transmission of a couple of sinusoidal signals, whose power is measured at the receiver, thus providing the differential attenuation measurements from which IWV estimates can be in turn derived. In 2018, a prototype instrument providing such differential attenuation measurements was completed and set up for a first measurement campaign aimed at demonstrating the NDSA method. By the end of June 2022, the instrument was profoundly modified and upgraded so that a second measurement campaign could be carried out from 1 August to 30 November 2022. The transmitter was placed on the top of Monte Gomito (44.1277°lat, 10.6434°lon, 1892 m a.s.l.) and the receiver on the roof of the Department of Information Engineering of the University of Florence (43.7985°lat, 11.2528°lon, 50 m a.s.l.). The resulting radio link length was 61.15 km. Four ground weather stations of the regional weather service were selected among those available. In this paper, we describe the upgraded instrument and present the outcomes of the new measurement campaign, whose purpose was mainly to compare the IWV estimates provided by the instrument with the ground sensor measurements of air temperature, air humidity, barometric pressure, and rainfall. In particular, we show that the temporal trends of the two IWV estimates are qualitatively consistent, and that the instrument is able to provide IWV estimates also in the presence of fog and rainfall. Conversely, a quantitative evaluation through comparison with IWV data from point weather station measurements appears challenging due to the significant spatial variability in temperature and relative humidity, even between couples of stations that are quite close to each other.

High-sensitivity humidity sensor based on Mach-Zehnder interferometer in seven-core fiber

A Mach-Zehnder Interferometer (MZI) based on seven-core fiber (SCF) for humidity sensing is proposed and experimentally demonstrated. The MZI is formed by sandwiched a section of SCF in between two single mode fibers (SMFs), while a fiber taper and a brief multimode fiber (MMF) act as fiber couplers to excite and couple the intermodal interference in the SCF. The optical field distribution and coupling efficiency of the MZI with different SCF lengths are analysed. The theoretical results show that the MZI is sensitive to SCF lengths, and it is expected to obtain highly sensitive humidity response. Humidity sensing experiments shows a high sensitivity of 0.6603 nm/%RH over a relative humidity (RH) range of 44–83 %RH, and the maximum measurement uncertainty introduced by the long-term stability is 0.0006 %RH. Human respiration measurement exhibits the response time and recovery time of the MZI are 0.44 s and 1.24 s respectively. The temperature effect is also experimentally investigated. Such an all-fiber MZI presents advantages of simple configuration, high sensitivity and good stability, making it has potential in humidity measurement fields.

Comparison of Indoor Climate between Wooden wall Construction and Concrete Wall Construction during Winter Season

Abstract This research aims to determine the importance of thermal comfort in buildings, especially residential houses, with a focus on two types of houses that have different structures as a comparison. The research also focuses on productive rooms that are frequently used every day, considering the long duration of use. Data collection methods include distributing questionnaires to residents, as well as a quantitative approach using experiments and thermal measurements of temperature and humidity in each room, including surface measurements to compare the two types of buildings. The analysis results show that there are differences in thermal comfort between the two types of houses. Houses with wooden construction show relative humidity that reaches a comfortable point (45-65%), while houses with concrete construction tend to move cold temperatures from outside to indoors more quickly. Although efforts have been made to achieve thermal comfort in every room, the main challenge remains related to the energy consumption of artificial comfort systems. The study location in Japan took into account the different outdoor temperature variations each season. The findings we got were that houses with wooden construction walls tend to be warmer due to several factors, one of which is that this building is an apartment type with openings that tend to be smaller compared to buildings with wooden construction walls which are a traditional Japanese house type with wide openings. The measurement results using PMV analysis for both buildings were measured at 2 times at the same time, namely during the day and at night. Measurements were carried out in the living room as a comparison room with the function of a room that has the same user interaction between the two buildings. Honjo Nishi Danci Apartment (concrete wall construction) has a comfort level in the quite comfortable category compared to the living room in the apartment. Kitakyushu Islamic Cultural Center (wooden wall construction). Data was taken when both buildings did not turn on the air conditioner so that the data taken could be comparable. At night, the conditions in the living room have a slightly warm sensation because the user uses air conditioning in the room because the user sleeps in this room. the conditions in the living room at the Islamic Cultural Center have a cold sensation due to the lack of activity and use of this room. So the sensation at night tends to be cold. These findings can guide building designers in developing architectural solutions that are sustainable and focused on indoor comfort in winter.

MZI-based high intensity responsive sandwiched multi-layer fiber optic humidity sensor

This paper presents a multi-layer optical fiber humidity sensor based on dual-beam Mach-Zehnder interference (MZI) for optical intensity sensitivity. The sensor is fabricated using a large-scale axial offset fusion technique between a multimode fiber (MMF) and an offset hole two-core fiber (OHTC), making it suitable for agricultural and health monitoring applications. The 27 μm axial offset enables tilted light incidence, enhancing environmental sensitivity. With a single-cycle Graphene oxide (GO) coating of approximately 22 nm, the MMF-OHTC structure achieves high humidity sensitivity (0.39 dB/%RH) over the 25 %-80 % RH range with excellent linearity (R2≈0.99). The sensor exhibits stable, rapid response (2.52 s/0.46 s) and low temperature cross-sensitivity (0.06 %RH/°C). When combined with a hollow-core fiber Fabry-Perot interferometer (HCF-FPI), the system allows zero cross-talk simultaneous humidity and temperature measurements, expanding the potential applications of multi-layered structures in multifunctional detection systems.

Assessment of Relative Humidity Measurements from INSAT–3D/3DR Sounder with Radiosonde and Satellite Measurements over India

Assessment of Relative Humidity Measurements from INSAT–3D/3DR Sounder with Radiosonde and Satellite Measurements over India

Evaluation of the Effect of Thermal Comfort in PMV-Method Classrooms on Teacher Work Stress Levels in the Dry Tropics (Study at Beru Elementary School, Sikka Regency)

This study aims to evaluate the effect of classroom thermal comfort on the level of teacher work stress in a dry tropical region (Study at SDI Beru, Sikka Regency), using the PMV (Predicted Mean Vote) method. Thermal comfort, which includes temperature, humidity, and air flow, is very important to create a conducive learning environment. Temperature and humidity measurement data were collected using temperature and humidity measuring devices model GSP-6 and RC-4HC for a certain period. In addition to using PMV, this study also used Regression and Correlation data analysis using SPSS. The sample used was a saturated sample. The results obtained in this study indicate that based on the PMV calculation, it was obtained that the temperature and humidity in the classroom varied and often exceeded the ideal comfort range. This condition can increase the level of teacher work stress and reduce productivity, this is in line with the results obtained from the SPSS program obtained validity and reliability testing using SPSS software there are 50 valid and reliable statements, the results of the analysis show that there is a significant linear relationship between work stress and thermal comfort (F Linearity = 30.454; Sig Linearity = .000). Based on these calculations, it can be seen that the regression coefficient value of the thermal comfort variable (X1) is 0.498 with a positive sign at sig 0.000 which is smaller than 0.05, namely 0.000 0.05. The regression coefficient value of the thermal comfort variable (X1) of 0.498 indicates that there is a positive relationship between thermal comfort and teacher work stress. This means that every one unit increase in thermal comfort will be associated with a 0.498 unit increase in the measured variable (teacher work stress). The significance value (p-value) of 0.000 is smaller than 0.05 (0.000 0.05). This shows that the results are statistically significant. In other words, there is strong evidence to state that thermal comfort has an effect on teacher work stress. So it can be interpreted that thermal comfort has a positive effect on teacher work stress.

Performance Analysis of Tropospheric Radio Refractivity along with Refractivity Gradient and Effective Earth Radius in the Coastal Zone of Nigeria

Study’s Excerpt Analysis of the variability in tropospheric radio refractivity in Ogoja and Warri, Nigeria, was carried out by examining a 42-year dataset (1981-2022) of meteorological factors obtained from NASA. The contributions of dry and wet terms to radio refractivity variations were identified and key parameters such as refractivity gradients and the effective earth radius (k-factor) for both locations were evaluated. The radio wave propagation in the region is lowest during the dry season. Full Abstract Radio refractivity is the ratio of the velocity of radio waves in a specific medium to that in free space. Radio waves propagate according to variations in tropospheric radio refractive index. This study used the refractive index and other pertinent meteorological factors to calculate the radio refractivity of the seasonal troposphere and analyse its variability with monthly temperature, relative humidity, and atmospheric pressure measurements that were collected from the National Aeronautic and Space Administration (NASA) for Ogoja and Warri over a forty-two-year period (1981 to 2022). We looked at the proportion contributions of the dry and wet term radio refractivity, the refractivity gradient, and the effective earth radius. The outcome signified that in the two locations, radio refractivity values were lowest for the dry season and highest during the rainy season. For Ogoja and Warri, the highest and lowest average radio refractivity values recorded in the wet and dry seasons are, respectively, 382.9085 N-units in May, 346.4311 N-units in January, and 390.9042 N-units in April, 370.3009 N-units in January. For Ogoja and Warri, the wet term (Nwet) provides 31.5210 % and 30.1793%, respectively, to the primary variation in radio refractivity's overall value, whereas the dry term (Ndry) adds up to 69.8207 % and 68.4790 %. Mean refractivity gradients of -43.8326 and -44.5326 N-units/km were found in the subject areas under examination. Furthermore, it was discovered that the mean effective earth radius (k-factor) for Warri and Ogoja were 1.3959 and 1.3873, respectively. The values provided represent the propagation conditions of superrefraction.

A Real-World Analysis of Weather Variation on Disease Activity and Patient-Reported Outcomes in Psoriatic Arthritis.

Patients with inflammatory articular diseases, such as psoriatic arthritis (PsA), report weather changes in their symptoms. Our objective was to investigate the correlation between weather variation, disease activity (DA), and patient-reported outcomes (PROs) in patients with PsA. Hourly measurements of temperature, relative humidity, and pressure were obtained from 2015 to 2020 in Montreal (through Environment Canada) and were matched with DA and PROs of patients with PsA enrolled in Rhumadata. The differences in mean DA and PROs were examined between winter and summer. Pearson correlation coefficients were calculated between clinical profile and weather measurements. Among patients with PsA, 2665 PROs were collected for a total of 858 patients. The Clinical Disease Activity Index (P = 0.001) and Simplified Disease Activity Index (P < 0.001) were lower in winter. In summer, positive correlations were found between humidity and symptoms (using patient global assessment, fatigue, pain, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index), whereas negative correlations between temperature and Health Assessment Questionnaire-Disability Index were reported. In winter, positive correlations were observed between temperature, fatigue, and pain. This is the first study to investigate weather variations through subjective and objective PROs matched with patients with PsA. Statistically significant differences in clinical profile were evident between winter and summer, as well as in their correlation with weather measurements. However, these distinctions lack clinical significance, suggesting a small impact on patients with PsA.

High sensitivity, thermal noise-driven aluminum-based resonant MEMS humidity sensor

The integration of connected devices and the Internet of Things in the era of Industry 4.0 has led to the transformation of various sectors. Sensors, particularly for humidity measurement, play a pivotal role in applications such as respiration and wound monitoring, human–machine interfaces, fuel cells, and circuit failure detection. While conventional humidity sensors dominate the market, gravimetric-based sensing offers promise but faces challenges due to complex fabrication, high cost, and nonlinearity. This study explores gravimetric platforms for humidity sensing and proposes linear and nonlinear schemes to detect humidity. The linear sensors exhibit consistent frequency shifts with humidity changes, while the nonlinear sensors introduce a turn-around point where nonlinear effects counteract mass-loading. We address this limitation by splitting the dynamic range into low and high ranges on either side of this point, thereby creating one-to-one relationships. Both sensor types demonstrate high sensitivity (from 39068 to −23568 ppm/%RH for nonlinear and 5809 ppm/%RH for linear) and repeatability, emphasizing their suitability for real-time humidity monitoring. Moreover, the thermal noise-driven resonators underlying the sensors do not require external input, thereby enhancing their suitability for low-power applications. These findings provide a foundation for innovative real-time sensing applications and offer insights into optimizing sensitivity and stability in humidity sensing and other applications.

Construction and Preparation of the Novel ADN/CL-20 Cocrystal via Directional Hydrogen Bonding Design for Turning Hygroscopicity.

Ammonium dinitramide (ADN), as a novel and environmentally friendly oxidizer, has strong hygroscopicity when exposed to high-humidity air, which seriously hinders its application in solid propellants. Modification of oxidizers by cocrystallization is an effective strategy to improve the hygroscopicity of energetic components. In this paper, the theoretical simulation of ADN/CL-20 cocrystals was developed via a directional hydrogen bonding design to establish a cocrystal with improved hygroscopicity. Intermolecular interaction analyses reveal that hydrogen bonds and van der Waals interactions synergistically lead to the formation of cocrystals. The ADN/CL-20 cocrystal was prepared experimentally by the spray drying self-assembly technique, and the corresponding thermal analysis and sensitivity properties were conducted to illustrate the thermal stability and high safety. Furthermore, the critical relative humidity (CRH) measurement was carried out to evaluate the hygroscopicity of the cocrystal, exhibiting a certain degree of antihygroscopic effect with a CRH of 65%. The hydrogen bonds formed between ADN and CL-20 saturate the ammonium ions of ADN, further preventing ADN from absorbing water molecules in the air. The ADN/CL-20 cocrystal has high specific impulse characteristics (Isp: 272.6 s). Accordingly, this work clearly demonstrates that the ADN/CL-20 cocrystal is expected to be used in a solid propellant to make up for the deficiency of the ADN oxidizer.

M13 bacteriophage-based high-sensitivity Fabry-Pérot etalon for detecting humidity and volatile organic compounds

Various sensor applications have been developed for protection against hazardous environments, and research on functional materials to enhance performance has also been pursued. The M13 bacteriophage (M13) has found utility in sensor applications like disease diagnosis and detection of harmful substances due to its potential for controlling interaction with target substances through adjustments in electrochemical and mechanical properties via genetic engineering technology. However, while optimizing reactivity or binding affinity between M13 and target materials is crucial for sensor performance enhancement, precise dynamic measurement methods for this were lacking. This study demonstrates the application of an M13-based dynamic actuator in a Fabry–Pérot etalon (M13-FPE) as a spacer for precise measurement of humidity and reactivity to volatile organic compounds (VOCs). The transmission spectrum is optimized by adjusting the reflectance and cavity gap size (dM13) of the two mirrors comprising the M13-FPE, and changes are measured in a rainbow-color-dotted (RCD) pattern using a customized spectrometer. Utilizing the peak wavelengths of the RCD pattern, the change in dM13 is dynamically and precisely measured, revealing approximately 3% and 0.3% swelling for ethanol and isopropyl alcohol, respectively. M13 demonstrates binding affinities of 827 ppb and 158 ppb for ethanol and isopropyl alcohol, respectively, with its low reactivity measured precisely, exhibiting an error of 0.03 nm using the peak wavelength change rate.