Ambient Humidity Research Articles

Validation of livability environmental limits to heat and humidity.

Rising global temperatures, driven by climate change, pose a threat to human health and regional livability. Empirical data and biophysical model derived estimates suggest that the critical environmental limits (CEL) for livability are dependent on ambient temperature and humidity. We use a well-validated, physiology-based, six-cylinder thermoregulatory model (SCTM) to independently derive CELs during sustained minimal, light, and moderate activity across a broad range of ambient temperatures and humidity levels and compare to published data. The activity and environments were considered livable if predicted core temperatures did not reach 38±0.25°C within six hours. The outcomes for minimal activity revealed CELs ranging from 34°C/95% RH to 50°C/5% RH. Corresponding dry heat losses ranged from 14 W·m-2 and -72 W·m-2 (negative = heat gain) and evaporative heat losses ranged from 39 W·m-2 to 104 W·m-2. The wet bulb temperature (Twb) at the CELs ranged from 33.3 to 20.9°C. Activity shifted CELs toward lower temperatures and humidities. Importantly, our predicted CELs largely agree with observed livability CELs from physiology and those from a biophysical model. The physiology-grounded SCTM has utility for assessing the impact of climate change on regional livability.

Combined Effect of Ambient Temperature and Relative Humidity on Skin Aging Phenotypes in the Era of Climate Change: Results From an Indian Cohort Study.

Background: There is no doubt that global warming, with its extreme heat events, is having an increasing impact on human health. Heat is not independent of ambient temperature but acts synergistically with relative humidity (RH) to increase the risk of several diseases, such as cardiovascular and pulmonary diseases. Although the skin is the organ in direct contact with the environment, it is currently unknown whether skin health is similarly affected. Objective: While mechanistic studies have demonstrated the mechanism of thermal aging, this is the first epidemiological study to investigate the effect of long-term exposure to heat index (HI) as a combined function of elevated ambient temperature and RH on skin aging phenotypes in Indian women. Methods: The skin aging phenotypes of 1510 Indian women were assessed using the Score of Intrinsic and Extrinsic Skin Aging (SCINEXA™) scoring tool. We used data on ambient temperature and RH, combined into an HI with solar ultraviolet radiation (UVR), and air pollution (particulate matter <2.5 µm [PM2.5]; nitrogen dioxide [NO2]) from secondary data sources with a 5-year mean residential exposure window. An adjusted ordinal multivariate logistic regression model was used to assess the effects of HI on skin aging phenotypes. Results: HI increased pigmentation such as hyperpigmented macula on the forehead (odds ratios [OR]: 1.31, 95% confidence interval [CI]: 1.12, 1.54) and coarse wrinkles such as crow's feet (OR: 1.17, 95% CI: 1.05, 1.30) and under-eye wrinkles (OR: 1.3, 95% CI: 1.15, 1.47). These associations were robust to the confounding effects of solar UVR and age. Prolonged exposure to extreme heat, as indicated by high HI, contributes to skin aging phenotypes. Conclusion: Thus, ambient temperature and RH are important factors in assessing the skin aging exposome.

Climate change and plant pathogens: Understanding dynamics, risks and mitigation strategies

AbstractClimate change is reshaping the interactions between plants and pathogens, exerting profound effects on global agricultural systems. Elevated tropospheric ozone levels due to climate change hinder plant photosynthesis and increase vulnerability to biotic invasion. The prevailing atmospheric conditions, including temperature and humidity, profoundly influence fungal pathogenesis, as each stage of a pathogen's life cycle is intricately linked to temperature variations. Likewise, climate change alters bacterial behaviour, fostering increased production of extracellular polysaccharides by plant‐pathogenic bacteria in warmer temperatures. Heat‐adapted bacteria, such as Burkholderia glumea and Ralstonia solanacearum, are emerging as significant global threats as temperature rise. Viruses, too, respond dynamically to climate shifts, with certain species favouring warmer climates for replication, resulting in expanded geographical ranges and modified transmission patterns. Nematodes, formidable constraints in crop production, exhibit temperature‐dependent life cycles and would have potentially accelerated proliferation and distribution as global warming progresses. Molecular‐level changes in pathogenesis, induced by temperature fluctuations, influence various pathogens, thereby impacting their virulence and interactions with host plants. Modelling studies predict changes in disease risks and distributions under future climate scenarios, highlighting the necessity of integrating climate data into crop disease models for accurate forecasts. Mechanistic and observational models illustrate pathogen behaviours amidst changing environmental conditions, providing crucial insights into future disease dynamics. In addition, controlled experiments study disease responses under simulated climate scenarios, underscoring the urgency for comprehensive research to devise effective resistance strategies against severe plant diseases.

Study on influence of friction conditions on the friction and wear performance of high-speed rail brake materials under high humidity environment

Purpose Using the multifunctional friction and wear testing machine independently developed by the research group, the friction and wear tests of different friction conditions (contact pressure and sliding speed) are conducted on the brake materials of high-speed trains with the ambient humidity of 95% and the initial temperature of the disk of 200°C. Design/methodology/approach Friction and wear. Findings The test results show that changing the friction conditions has a significant effect on the braking performance of high-speed trains. Originality/value YES. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0171/

Effects of Various Packaging Materials on Physico-Chemical Characteristics of Vacuum Fried Carrot Chips during Storage

Aims: The objective of this study was to determine the effects of type of packaging materials and time of storage on the physicochemical characteristics of vacuum fried carrot chips. Place and Duration of Study: The research work was carried out at the Dept. of Processing and Food Engineering (P&amp;FE), Kelappaji College of Agricultural Engineering and Technology, Tavanur, Kerala during the year of 2019-20. Methodology: The vacuum fried carrot chips were packed into three different packaging materials namely low-density polyethylene stand pouch (LDPE), laminated aluminum flexible pouch and polypropylene. All three packaging materials were tested with and without N2 gas filling. The storage studies were conducted for the vacuum fried carrot chips which was fried under optimized processing conditions: Frying Temperature-100⁰C; Frying Pressure-13 kPa; and Frying Time- 20 min. The experimental study was conducted for 4 months period and data was recorded for every 30 days interval. The packed samples were stored at the ambient temperature (25±5ºC) and relative humidity (70±10%) for storage studies. The quality attributes such as moisture content, water activity, oil content, hardness and colour values of the chips were determined during the storage studies. Results: Based on the research study, the results shown that the oil content remained constant throughout 120 days of storage period in all packaging materials. The water activity, moisture content, hardness and colour values got increased with increase in storage time. The moisture content, water activity and hardness values were less in laminated aluminium pouches with N2 gas filling compared to polypropylene and LDPE.

Wildfire aerosols and their impact on weather: A case study of the August 2021 fires in Greece using the WRF‐Chem model

AbstractWildfires are significant contributors to atmospheric gases and aerosols, impacting air quality and composition. This pollution from fires also affects radiative forcing, influencing short‐term weather patterns and climate dynamics. Our research employs the Weather Research and Forecasting model coupled with Chemistry (WRF‐Chem) to investigate the repercussions of wildfires on aerosol abundances and associated immediate weather responses. We examine the summer season of 2021, a period marked by severe wildfire events in the country during a heatwave period. We conducted sensitivity experiments including and excluding wildfire emissions to measure their effects on aerosol optical depth (AOD), radiative forcing, and weather features such as temperature, humidity, clouds, and atmospheric circulation. Our findings demonstrate that the radiative impacts of wildfires negatively influence the local temperature over the fire smoke plume‐affected areas. Conversely, neighbouring areas of continental Greece experience increases in temperature due to remote effects of wildfire emissions, caused by meteorological feedbacks that reduce atmospheric humidity. Crucially, including fire emissions significantly improves the simulated surface temperatures predicted by the model over the Greek domain. Our work demonstrates that wildfire‐generated aerosols can significantly impact weather conditions and highlights the importance of including both local radiative effects and remote feedback for achieving more accurate weather prediction.

Monitoring the anticorrosion performance of developed epoxy-based paint formulations on metallic surfaces by electrochemical impedance spectroscopy

Purpose This study aims to investigate the impact of varying solid ratios in epoxy-based formulations on their corrosion resistance. The amounts of epoxy resin in the formulations were kept constant, and the behavior of paints with varying filler ratios was compared. It also examines the tensiometric and rheological properties of these formulations. Design/methodology/approach Three distinct epoxy-based formulations cured with amine compounds were prepared. The formulations underwent various testing protocols to evaluate their performance: coating tests: coated panels with cross lines were exposed to humidity and corrosive atmospheres. Tensiometric Measurements: Conducted using pendant and sessile drop methods. Rheological characterizations: ıncluded flow tests, oscillatory amplitude sweeps and three-interval thixotropy tests. Corrosion resistance assessment: after the panels were immersed in methanol for one week, measurements were taken using electrochemical impedance spectroscopy. Additional tests: neutral salt spray (NSS) and humidity testing. Findings The study observed that the coated panels, after exposure to NSS and humidity testing, demonstrated corrosion resistance within acceptable limits as defined by the ISO 12944-6 standard. Results indicate that the epoxy-based formulations show potential for improvements in paints and coatings, suggesting promising advancements in their anticorrosion performance. Originality/value This research provides insights into how the solid ratios in epoxy-based formulations influence their performance, particularly in terms of corrosion resistance, tensiometric and rheological properties. The findings contribute to the development of more effective epoxy resin-based coatings for industrial applications.

Chronobiological perspectives and meteorological associations in symptomatic popliteal artery aneurysms

ABSTRACT The potential influence of circadian rhythm, seasonal variations, and alterations in meteorological parameters has been studied across various vascular events. However, there is a lack of evidence on the potential chronobiological impacts on thromboembolic events related to the most common peripheral aneurysm, the popliteal artery aneurysm (PAA). Data was obtained from a German PAA registry and the German Meteorological Service (Deutscher Wetterdienst). In this observational cohort study seasonality and chronobiology as well as associations with meteorological parameters of symptomatic PAA were investigated. In a multivariate logistic regression analysis, it was further analyzed whether meteorological parameters could distinguish asymptomatic from symptomatic patients in the registry. Of 1200 registered PAA, n = 142 PAA presented with acute limb ischemia between February 2011 and September 2022. More symptomatic patients (57.0%) presented to the hospital between January and June than in the second half of the year with a nadir in the fall season. Symptom onset was predominantly in the morning hours (39.5%). Atmospheric pressure and humidity values from the index dates diverged from a normal distribution showing a bimodal (“double-peak”) configuration. Most patients developed symptoms after a reduction in temperatures compared to 1 or 2 d prior to the index date. However, we found evidence for an interaction between age and temperature difference, where the effects of a decreasing temperature fade with increasing age. Facing the complexity of individual-environment interactions, further investigations are needed to determine whether meteorological parameters are true risk modifiers or surrogates for seasonal differences and altered behaviors.

Evaluating the Influence of Thin Film of Water on the Frequency Dependences of Transmission Line S-Parameters at Positive and Negative Temperatures

Relevance. Provision of reliable and uninterrupted radio communication is critically important under changing climatic conditions of its operation. The combined effect of temperature and humidity can lead to changes in the electrical characteristics of transceiving devices and thereby disrupt the communication channel. In difficult climatic conditions of operation, due to constant temperature changes on the surface of the printed circuit boards, which are part of them, condensation can form, affecting the performance of the entire device. In this regard, the electrical characteristics change, which must be taken into account when designing critical REE. When designing transmission lines on printed circuit boards, it is reasonable to evaluate climatic impacts on it in a wide frequency range, which requires the development of new models and methods that allow taking into account these impacts.Goal of the work: to evaluate the influence of the temperature of a thin film of water on the surface of a microstrip transmission line on its frequency dependences of S-parameters. Finite element methods and laboratory experiment were used.Results. A methodology to account for the effects of ambient temperature and humidity on the electrical characteristics of a microstrip transmission line (MTL) is presented, which allows evaluating the variation of the S-parameters of the line over wide ranges of frequencies, air temperature and humidity, as well as the chemical composition of the environment. The S-parameters of water in a container placed inside a coaxial chamber are measured over the frequency and temperature ranges of 10 MHz to 12 GHz and minus 50 to 100℃, respectively. Using the presented model, the frequency dependences of the electrical conductivity of water at different temperatures are calculated. It is shown that at positive temperature, the electrical conductivity can reach 6.5 Sm/m and at negative temperature it can reach 1.3 Sm/m. Using the developed methodology, the influence of different water electrical conductivity on the S-parameters of MTLs is evaluated. The influence of water and ice layer thickness on the S-parameters of MTLs was shown. It is found that models describing the electrical conductivity of water have an excellent influence on the electrical parameters of the transmission line. Novelty. A method of accounting for the influence of ambient temperature and humidity on the S-parameters of the transmission line is presented, which is characterized by the use of a model of water conductivity based on insertion losses calculated from the measured S-parameters of a coaxial chamber with water in the container when its temperature is changed. Practical significance: a model and a methodology for taking into account the impact of temperature and humidity of the environment on the MTL characteristics are presented, allowing estimating the S-parameters of the line in a wide range of frequencies, air temperature and humidity, as well as the chemical composition of the environment.

Origin of Persisting Photoresponse of One-Year Aged Two-Dimensional Lead Halide Perovskites Stored in Air under Dark Conditions.

Two-dimensional halide perovskites are promising for advanced photonic, optoelectronic, and photovoltaic applications. However, their long-term stability is still a critical factor limiting their implementation into further commercial applications. Here, we present an environmental stability analysis of BA2(MA)n-1PbnI3n+1 (BA = C4H12N+, MA = CH6N+) two-dimensional perovskites with the lowest quantum well thicknesses of n = 1 and n = 2, after 1 year of aging under ambient humidity, oxygen content, and light conditions. We observed that both crystal phases (n = 1 and 2) degraded similarly, resulting in the removal of organic components and crystal decomposition into PbI2, Pb oxides, and Pb hydroxides. However, we have found a significant difference between their aging under ambient light and dark conditions, affecting their degraded morphology and photoactivity. Both crystal phases exposed to ambient light aged into a morphology characterized by the formation of several pinholes and voids, accompanied by photoluminescence degradation. Samples stored under dark conditions surprisingly preserved their photoluminescence activity, which morphologically aged into microrod structures. We conclude that the observed loss of photoactivity of 2D perovskites aged under ambient light is attributed to photoaccelerated degradation processes causing faster crystal surface photo-oxidation accompanied by a creation of multiple I vacancies and hydration of the inner crystal. The retainment of photoactivity in 2D perovskites aged under dark conditions is attributed to slower surface oxidation processes into Pb salts, as confirmed by X-ray photoemission spectroscopy. The formed surface layer even allows for a layer-by-layer degradation and acts as a protection barrier against further additional loss of I atoms and the consequent hydration of the inner part of samples. We demonstrate that light is the most critical external factor accelerating 2D perovskite degradation processes in ambient air and thus affecting their long-term stability. We conclude in this work that perovskite material structural engineering together with their surface passivation or encapsulation strategical techniques applied is an essential step for their further application into long-term stable commercial devices.

The Efficacy of Nutritional Strategies and Ergogenic Aids on Acute Responses and Chronic Adaptations to Exertional-Heat Exposure: A Narrative Review

Global warming is attributed to an increased frequency of high ambient temperatures and humidity, elevating the prevalence of high-temperature-related illness and death. Evidence over recent decades highlights that tailored nutritional strategies are essential to improve performance and optimise health during acute and chronic exertional-heat exposure. Therefore, the purpose of this review is to discuss the efficacy of various nutritional strategies and ergogenic aids on responses during and following acute and chronic exertional-heat exposure. An outline is provided surrounding the application of various nutritional practices (e.g., carbohydrate loading, fluid replacement strategies) and ergogenic aids (e.g., caffeine, creatine, nitrate, tyrosine) to improve physiological, cognitive, and recovery responses to acute exertional-heat exposure. Additionally, this review will evaluate if the magnitude and time course of chronic heat adaptations can be modified with tailored supplementation practices. This review highlights that there is robust evidence for the use of certain ergogenic aids and nutritional strategies to improve performance and health outcomes during exertional-heat exposure. However, equivocal findings across studies appear dependent on factors such as exercise testing modality, duration, and intensity; outcome measures in relation to the ergogenic aid’s proposed mechanism of action; and sex-specific responses. Collectively, this review provides evidence-based recommendations and highlights areas for future research that have the potential to assist with prescribing specific nutritional strategies and ergogenic aids in populations frequently exercising in the heat. Future research is required to establish dose-, sex-, and exercise-modality-specific responses to various nutritional practices and ergogenic aid use for acute and chronic exertional-heat exposure.

Digital twin for decision support system of industrial utility management

Manufacturing and industrial operations rely heavily on energy that is generated mostly from fossil fuels, such as coal, oil, and natural gas, which harm the environment and contribute to climate change. Thus, renewable energy is being integrated into industrial processes to lessen environmental effects and reduce fossil fuel usage. However, the renewable source performance process can be greatly affected by disturbances and constraints, such as ambient air temperature and relative humidity, minimum utility consumption, and the total energy required, making effective control difficult. This study proposes a digital twin built with machine learning regression techniques for load demand forecasting as a decision-support system for industrial utility management. From the results, the ensemble tree (ET) model produced the highest accuracy, based on validation and test dataset root mean squared error values of 23.164 and 27.558, respectively, and R2 values of 0.96 and 0.95, respectively. The digital twin and load demand forecasting approaches effectively created an efficient operating schedule for industrial utility management. The ET model had a total error of 23.86%, substantially lower than the average load demand's total error of 65.29%. Therefore, the ET model with weather conditions in four scenarios could be recommended to optimize energy utilization when creating the operating schedule.

Multistimuli-Responsive Soft Actuators with Controllable Bionic Motions.

Soft actuators with biomimetic self-regulatory intelligence have garnered significant scientific interest due to their potential applications in robotics and advanced functional devices. We present a multistimuli-responsive actuator made from a carbon nitride/carbon nanotube (CN/CNTs) composite film. This film features a molecular switch based on reversible hydrogen bonds, whose asymmetric distribution endows the film with the ability to absorb water unevenly and convert molecular motion into macroscopic movement. By incorporating carboxylated CNTs, the film demonstrates improved mechanical properties and actuation performance. Under ambient humidity stimuli, the actuator can autonomously generate walking and tumbling motions. The CN/CNTs composite film's actuating behaviors are programmable, enabling diverse deformation modes and complex biomimetic movements. Additionally, the film exhibits excellent photothermal conversion efficiency (74.10 °C/s), allowing for temperature and light-responsive actuation, which can be remotely controlled in real time. These features have enabled the creation of soft robots capable of complex biomimetic actions such as jumping, directional movement, and transporting objects. This research broadens the potential applications of CN-based actuators and paves the way for the development of intelligent soft robots.

Winter haze amplification by aerosol hygroscopic growth over eastern Indo- Gangetic Plain

Frequent occurrences of widespread winter haze over Northern India largely appear to originate from exceedingly high concentrations of fine particulate matter from anthropogenic emissions. However, the underlying mechanisms driving winter haze in Northern India are not well understood. This study employed a synergy of satellite and reanalysis data from 2006 to 2021 to assess the role of hygroscopic growth of aerosol optical depth in winter haze over the eastern Indo-Gangetic Plain. A method has been developed to extract dry aerosol optical depth from ambient aerosol optical depth to elucidate the origin of winter haze. About 31% of severe haze episodes (aerosol optical depth > 0.85) occurring under ambient humidity conditions decrease to below 5% for dry conditions, indicating the critical role of particle hygroscopic growth. The change in radiative forcing at the top of the atmosphere due to hygroscopic growth is relatively small compared to that at the surface and in the atmosphere, indicating enhanced atmospheric warming. The ubiquitous winter haze over the eastern Indo-Gangetic Plain is exacerbated by hygroscopic growth under high anthropogenic aerosol emissions, further aggravated through aerosol-radiation feedback. These results will be valuable in devising haze forecasts, implementing effective mitigation policies, and representing aerosol hygroscopicity in climate models.

Compact Layer‐Free Perovskite Solar Cells with Low‐Temperature UVO Photochemical Annealed Mesoporous TiO2 Layers

In recent years, the field of perovskite solar cells (PSCs) has seen rapid development, with most high‐efficiency devices incorporating dense titanium dioxide (TiO2) barrier layers and mesoporous TiO2 layers to enhance selective electron transport. However, the manufacturing process requires high‐temperature sintering steps above 450 °C, leading to significant energy consumption. In addition, this requirement greatly limits the potential applications of PSCs in the field of flexible electronics. This study introduces a new method for preparing dense‐layer‐free mesoporous PSCs using low‐temperature UVO annealing of m‐TiO2. UVO annealing effectively removes residual organic components from m‐TiO2 precursor films, enhances the conductivity and wettability of the films, thereby reducing carrier recombination and improving the performance of PSCs. Research has shown that PSC with a 40 min UVO annealed m‐TiO2 layer exhibits a final photoelectric conversion efficiency of 17.79%, comparable to devices with traditional high‐temperature annealed m‐TiO2 PSCs. In addition, after 7 days at room temperature and ambient humidity, the unpackaged device maintains a maximum conversion efficiency of 84%. These findings indicate that UVO light annealing is a feasible alternative to high‐temperature annealing, providing a simpler, more cost‐effective, and energy‐saving method for the preparation of metal oxide electron transport layer in PSCs.

An innovative method for mesoscale modelling of moisture diffusion in concrete

Moisture diffusion influences the durability and long-term performance of concrete and whilst it predominantly occurs via the cement matrix and Interfacial Transition Zone, most existing models consider concrete to be homogeneous. This paper introduces a novel micro-meso model that employs random packing and Voronoi tessellation. Rayleigh-Ritz pore distribution and Brunauer-Skalny-Bodor models are combined to determine the radius and fraction of various pores. The results indicate that relative humidity diffuses faster with increasing temperature, decreasing ambient relative humidity and tortuosity. Ambient relative humidity has a greater influence on diffusion compared to temperature and tortuosity. Numerical and experimental comparisons demonstrate that the proposed methodology effectively captures relative humidity distribution across various scenarios. Furthermore, explicit pore network modelling incorporates key parameters for a more accurate analysis. Integrating the proposed methodology into a fully coupled hygro-mechanical framework can potentially yield more accurate predictions of mechanical behaviour; enhancing the reliability of long-term performance assessments and enabling more durable concrete design.

Content validation of the nursing diagnosis “ineffective protection” in the context of adolescents with cancer

ObjectiveTo analyze the relevance of a set of clinical elements to represent the content domain of the nursing diagnosis Ineffective Protection. Design and methodsThis study employed content validation, using expert judgment to assess the appropriateness of clinical indicators, etiological factors, and conceptual and operational definitions, integrating the collective wisdom framework, the theory of predictive diversity, and the determination of rater skill level. ResultsFrom the middle range theory, 28 clinical indicators and 17 etiological factors were identified, which were rated by 34 raters. The analysis showed that the clinical indicators restlessness and insomnia and the etiological factors ambient temperature and humidity were not considered relevant for the nursing diagnosis of Ineffective Protection, because the median content validity index was lower than 0.9. ConclusionsContent validation verified that most of the components of the nursing diagnosis of Ineffective Protection were considered relevant by judges. Practical implicationsIt is believed that the data obtained can help nurses to more easily evaluate the related factors and clinical indicators of Ineffective Protection presented by adolescents with cancer, which favors the process of diagnostic inference.

Sustainable commercially-scaled greenhouse building cooling solution: Integrating PCM storage, desiccant wheels, and absorption chillers powered by dual-source solar/biomass energy

This research aims to address the critical need for sustainable cooling systems in greenhouses, particularly relevant in mitigating global warming impacts and enhancing food security worldwide. The urgency becomes more pronounced in locations experiencing high ambient temperature and humidity. The study introduces an innovative cooling system integrating Phase Change Material, a desiccant wheel, and an absorption chiller, powered by solar and biomass energy. This novel system aims to efficiently regulate temperature and humidity in greenhouse environments. The performance of this system is examined in Abu Dhabi, Doha, and Riyadh during the summer months, utilizing TRNSYS software for a medium-scale greenhouse model. Additionally, a comprehensive Life Cycle Assessment is carried out to quantify the environmental impacts of the proposed system. Results indicate that in Abu Dhabi, the system yields a Coefficient of Performance (COP) of 1.108, effectively maintaining indoor climate conditions. Similarly, Doha and Riyadh exhibit COPs of 1.015 and 0.827, respectively. In terms of solar energy utilization, Abu Dhabi demonstrates a solar fraction of 40.4, corresponding to the lowest Global Warming Potential (GWP) at 0.106 kg CO2eq per 1 kW of provided cooling capacity. Conversely, Riyadh records the highest GWP at 0.149 kg CO2eq, followed by Doha at 0.118 kg CO2eq. The Energy Payback Time (EPBT) for the system in Abu Dhabi is calculated to be 3.96 years, the shortest among the examined cities. In comparison, Doha and Riyadh present longer EPBTs of 4.48 and 5.83 years, respectively. These findings suggest that the proposed system offers a viable and environmentally friendly alternative to conventional greenhouse cooling approaches.

Preparation and Electrochemical Performance of Alkaline Earth Metal-Doped Nd2Ce2O7 Proton Conductor Hydrogen Separation Membranes

Nd2Ce2O7 is a rare earth oxide with a fluorite structure and exhibits proton conductivity. Alkaline earth metals (Mg, Ca, Sr, Ba) doped Nd2Ce2O7 powders were synthesized using the citrate sol-gel method. The doped samples retain the fluorite structure, and enhanced oxygen vacancy concentration. Notably, Nd1.85Mg0.15Ce2O7-δ exhibited the highest oxygen vacancy concentration, reaching an electrical conductivity of 2.91×10-2 S•cm-1 in a humid atmosphere of 20%H2 and 80%N2 at 900°C. Hydrogen separation membranes were fabricated using alkaline earth metal-doped Nd2Ce2O7 as the proton-conducting phase and Pt as the electron-conducting phase. The results indicated that Pt-Nd1.85Mg0.15Ce2O7-δ had the optimal hydrogen permeation flux, reaching 8.35×10-9 mol•cm-2•s-1 at 900°C. It demonstrated short-term stability in environments containing CO2 and H2O, and an increase in temperature and hydrogen partial pressure on the feed side enhanced hydrogen permeation, highlighting its potential as a hydrogen separation membrane material.

Assessment of a Cowl-Incorporated Wind-Powered Forced-Air Evaporative Cooler for Preservation of Fruit and Vegetables

This paper reports the performance of a cowl-incorporated wind-powered forced-air evaporative cooler for preservation of fruit and vegetables. The evaluation took place in the Department of Mechanical Engineering, Obafemi Awolowo University, Ile-Ife in October. Freshly harvested tomatoes were used in the evaluation as tomatoes were common locally and are highly perishable. The produce (2.5 kg) was kept in the cooling chamber of the evaporative cooler, and the changes in weight were observed three times daily until the produce had lost more than 7 % of its weight. The no-load cool air temperatures ranged between 27.3and 34.5oC corresponding to ambient dry bulb temperatures 29.0and 43.9oC respectively. The no-load cool air relative humidity ranged between 63.0 and 87.2% corresponding to ambient relative humidity of 40.8 and 79.5% respectively. The evaporative cooler no-load cooling efficiency was 66.7% while the cooling efficiency when loaded was 50.0%. The evaporative cooler was able to preserve tomatoes for 9 days losing 4.8 % weight. The evaporative cooler had the potential of effectively preserving fruit and vegetables without dependence on electricity. If used in windier and less humid regions, the average cooling efficiency of the evaporativecooler would be higher than that observed in this research.