High Relative Humidity Values Research Articles

Assessing the impacts of meteorological factors on freshwater consumption in arid regions and forecasting the freshwater demand

The continuously increasing consumption and scarcity of natural freshwater resources impose threats on different aspects of human life. This study investigated the possible influences of meteorological factors, e.g., relative humidity, temperature, and wind speed, on net freshwater consumption (NFWC). Additionally, we determined the seasonal variations in these factors and forecasted the consumption rate over five years. We took Kuwait as an example and analyzed daily readings obtained from 2014 to 2018 by the Directorate General of Civil Aviation and Ministry of Electricity and Water. The results showed that the consumption rate was affected positively by temperature and negatively by relative humidity. In the seasonality results, two groups characterizing the summer (May to October) and winter (November to April) seasons were obtained regarding the corresponding meteorological factors and net freshwater production (NFWP) and NFWC. The summer season showed high temperature, NFWC, and NFWP and low relative humidity values. In contrast, the winter season revealed high relative humidity and low temperature, NFWC, and NFWP values. The forecasting model is highly accurate and estimated that NFWC will reach 171,919 million imperial gallons/year by 2024. Thus, the obtained results and performed analyses assist in the future management and performance of installed desalination processes.

The changing extreme values of summer relative humidity in the Tarim Basin in northwestern China

Relative Humidity (RH) in the arid region of the Tarim Basin is crucial for many reasons. The Tarim Basin has experienced a tendency to become wetter in recent decades, and the RH there also shows an increase over the past decade. However, there has been little examination of these RH changes and especially the changes to the extremes. This study investigates the changes in extreme values and the probability density function (PDF) of summer RH using quantile regression during 2006–2018 to understand the possible reasons for the increase in the summer RH anomaly. We find that extremely high values of RH show a consistent significant increase, while extremely low values have no regionally consistent tendency. The overall average value of RH in the Tarim Basin becomes higher, contributed by the upper half of the PDF. To explore the physical mechanism for these changes, we examine the corresponding regional meteorological anomaly patterns. The patterns indicate that the anomalous southwesterly airflow at 500hPa brings ample moisture into the basin and the ground in the middle of the basin significantly cools down when an extreme wet event occurs, promoting the occurrence of the extreme high RH. In this process, the contributions of water vapor transport and temperature are of equal significance though with different relative timing. These corresponding regional meteorological patterns occur more often in the most recent decade, which coincides with the recent increase in RH extremes in this region.

Assessment of Structural Differences between Water-Extracted and Non-Extracted Hydro-Thermally Treated Spruce Wood by NIR Spectroscopy

Sitka spruce wood samples were subjected to different conditions of hydro-thermal treatment by varying the relative humidity (RH) and period of exposure at a constant temperature of 120 °C. Near infrared (NIR) spectroscopy, principal component analysis (PCA) and two dimensional correlation spectroscopy (2D-COS) were employed to examine the structural changes which occur in the wood samples during the applied treatment conditions and to quantify the differences between non-extracted and water-extracted wood specimens after the treatment. Modifications were dependent on the amount of water molecules present the medium and also on treatment time. Higher variations were observed for samples treated at higher RH values and for longer periods. At the same time, it was also observed that during the hydro-thermal treatment a high amount of extractives remain in the wood structure, extractives which vary in quantity and composition. PCA and 2D-COS made it possible to discriminate modifications in the wood samples according to treatment time and relative humidity. Non-extracted and water-extracted samples were also examined to identify the sequential order of band modification.

In situ monitoring of moisture uptake of flax fiber reinforced composites under humid/dry conditions

AbstractThe use of green materials such as natural fiber‐reinforced composites represents an increasingly stringent prerogative in the future planning of industrial and non‐industrial production. The optimization of these materials is the main aim of the current research, focused on the evaluation of the behavior of flax fiber reinforced composites exposed to isothermal adsorption and desorption cycles, at varying the partial pressure of water vapor (P/P0). For this purpose, the moisture uptake and the morphology changes of the composite material and their constituents were in situ monitored through a measurement protocol, by using a dynamic vapor sorption (DVS) analysis, coupled with an environmental scanning electron microscopy (ESEM) visual investigation. A dependence of moisture uptake and diffusivity on the composite morphology was clearly detected. In particular, no significant variation in the morphology of the specimen is noticed at low water vapor partial pressure (i.e., P/P0 up to 5.4%) due to the limited absorption capacity (i.e., lower than 1%). On the other hand, fibers morphology changes at increasing the partial pressure up to 25.1%, showing a sensitive increase in volume. This phenomenon becomes much more relevant for high relative humidity values (i.e., ~90%), reaching more than 6% of absorption capacity.

Variations in relative humidity across Poland and its possible impacts on outdoor thermal comfort: An analysis based on hourly data from 1995 to 2020

AbstractThis study investigated the variations in relative humidity (RH) and its impacts on outdoor thermal comfort in Poland. The study considered hourly RH data from 44 stations over the period 1995–2020. A countrywide declining trend in average RH was seen over the above period. This trend was more pronounced at stations in central and northwestern Poland. In the majority of the stations, in spring and summer, a statistically significant decline in the average RH was seen in the period 2008–2020 (second half of data) in comparison to that in the period 1995–2007 (first half of data). In all seasons, during the period 1995–2020, frequency distributions of RH corresponding to all stations were heavily left‐skewed and the peak occurred at an RH around about 90–95% or even higher. This indicated that high RH values are frequent in Poland. In the majority of the stations, an increase in the average number of hours per year above high percentiles of RH (95, 96th, 97th, 98th, 99th and 99.5th) and an increase in the average number of hours per year below low percentiles of RH (0.5th, 1st, 2nd, 3rd, 4th and 5th) were seen in the period 2008–2020 compared to that in the period 1995–2007. The above findings lead to the conclusion that occurrences of low and high extremes of RH have increased though the average of RH shows a decline. Also, in the majority of the stations, the number of hot–humid hours and the number of cold–dry hours have increased in the period 2008–2020 compared to those in the period 1995–2007. According to the Discomfort Index, over the period 1995–2020, the outdoor warm thermal comfort in Poland has declined due to high temperature and high humidity.

Analysis of heat stress and heat wave in the four metropolitan cities of India in recent period

Cities are becoming hotter day-by-day because heat is trapped near the earth's surface due to a decrease in green cover, rapid urbanization, energy-intensity activities, and concrete structures. The four major metropolitan cities of India, i.e. Kolkata, Chennai, Delhi and Mumbai, have experienced heat waves and heat stress frequently during the summer season. This study analyses heat wave and heat stress patterns in these cities using 30 years of data from 1990 to 2019 during the summer season. We used daily maximum temperature, relative humidity, wind speed and solar radiation datasets for the above mentioned period in this study. To understand the episode of a heat wave, we have used the 95th percentile method. Furthermore, we have also used Humidity Index (HD) to evaluate the degree of discomfort and the Universal Thermal Climate Index (UTCI) to categorize the level of heat stress. The analysis indicates that the number of heat wave events in the Delhi region is 26.31%, 31.58% and 63.16% higher than Kolkata, Chennai, and Mumbai regions respectively. It is also seen that the risks of extreme heat stress and dangerous-heat stroke events in the Chennai region during heat wave periods are higher than that experienced in other metropolitan cities because of high temperature with higher values of relative humidity. The risk of extreme heat stress is less in Delhi because of lower relative humidity compared to other metropolitan cities although temperature is higher in this region. However, the risk of extreme heat stress is lower in Mumbai region because of relatively lower temperature than Chennai during summer season. The likelihood of experiencing great discomfort during heat wave periods in Kolkata city is higher than that experienced in other metropolitan cities in India, however, during non-heat wave periods the probability of extreme discomfort is higher in Chennai.

Analysis of Ventilation Efficiency in the Earth Covered Magazine for Ammunition Storage Using Numerical Simulation

Internal environment parameters such as temperature, relative humidity and airflow velocity in ammunition storage facilities have a significant impact on the condition and overall life of ammunition, especially on the process of ammunition degradation in situations when their values deviate from required standards for safe storage. High temperatures inside the magazine, as well as in the ammunition packaging, can have a very negative effect on the structure of ammunition and explosives, and high values of relative humidity can result in corrosion and rapid decomposition of chemical compounds. Therefore, a properly designed ventilation system should ensure that the values of internal temperature and relative humidity are within the permitted limits, which is a very important aspect of the storage process itself, so that ammunition and explosives can be completely safe and ready for transport, use and handling. Experimental studies conducted in several magazines of ammunition and explosives in Bosnia and Herzegovina (BiH), had aim to monitor changes of environmental parameters such as temperature, relative humidity and airflow velocity. During these experimental measurements, high values of relative humidity were in these magazines observed, as well as uneven airflow in some ventilation ducks. The main cause of such measured values can be related to the inadequate performance of the natural ventilation system of the analysed magazines. Using numerical simulations (finite volume method) in the ANSYS – Fluent program, the analysis of the existing ventilation system of earth covered magazine in BiH from the aspect of airflow velocity was performed, as well as analysis of modifications that can improve airflow within the analysed magazine. The results of numerical simulation for the existing state of analysed magazine corresponded to the results of airflow measurements at certain places in the magazine. It was confirmed that the existing ventilation system does not provide proper ventilation, which further causes higher relative humidity values. The results of numerical simulation for the proposed modifications of the ventilation system have shown significantly better air circulation in the magazine, i.e. that a more efficient natural ventilation was achieved.

Effects of temperature and relative humidity on the COVID-19 pandemic in different climates: a study across some regions in Algeria (North Africa).

After more than a year from the first confirmed cases of coronavirus (COVID-19) disease, the role of meteorological factors in the transmission of the virus still needs to be correctly determined. In this scenario of deep uncertainty, the present study aims to investigate the effects of temperature and relative humidity on daily new cases of COVID-19. For this purpose, the COVID-19’s development of infection in fourteen Algerian cities characterized by different climatic conditions, during the period from April 1, 2020, to August 31, 2020, has been investigated. A detailed time series analysis along with linear regression was used to state a possible correlation among some climate’s factor variability (temperature and relative humidity) and daily new confirmed cases of COVID-19. The results showed a weak correlation between daily new cases of COVID-19 and meteorological factors throughout the selected regions. In addition, we concluded that the COVID-19 could fit to high or low values of temperature and relative humidity, and other factors not climates could affect the spreading of the virus like demography and human contact. So, after the discovery of the vaccine and before vaccination of 70% of the world’s population, living with the virus has become an inevitable reality, and it is mandatory to apply the sanitary procedures to slow down the COVID-19 transmission.Graphical abstract

Commercially relevant water vapor barrier properties of high amylose starch acetates: Fact or fiction?

Starches have recently regained attention as ecofriendly barrier materials due to the increased demand for sustainable packaging. They are easily processable by conventional plastics processing equipment and have been utilized for oil and grease barrier applications. While starches have excellent oxygen barrier properties and decent water barrier properties at low relative humidity (RH), they are moisture sensitive, as demonstrated by the deterioration of the barrier properties at higher RH values. Starch esters are chemically modified starches where the hydroxyl group of the starch has been substituted by other moieties such as acetates. This imparts hydrophobicity to starches and has been claimed as a good way of retaining water vapor barrier properties of starches, even at high RH conditions. We studied the water vapor barrier properties of one class of starch esters, i.e., high amylose starch acetates that were assumed to have good water vapor barrier properties. Our investigations found that with a high degree of substitution of hydroxyl groups, the modified starches did indeed show improvements in water vapor response as compared to pure high amylose starch films; however, the barrier properties were orders of magnitude lower than commercially used water vapor barriers like polyethylene. Even though these materials had improved water vapor barrier response, high amylose starch acetates are likely unsuitable as water vapor barriers by themselves, as implied by previous literature studies and patents.

Oxygen Depletion Testing of Metals

The altered nature of archaeological metals means they deteriorate at much lower relative humidity (RH) conditions than historical metals. The study of deterioration for such materials is hampered by their complexity, variability and difficulties in measuring deterioration. Placing an object in a sealed container, controlling the RH and pollutant gases and measuring any decrease in oxygen concentration is an accessible method to measure the deterioration rate. It has been used for research into suitable environmental conditions to manage the deterioration rates of such artefacts, including the differences in the response of artefacts from different excavation sites. Some objects need the careful control of RH to low values; this is expensive to maintain and poses risks to other artefacts displayed together. Many objects are actually stable up to quite high RH values, and oxygen depletion testing has been used to identify those that can be safely displayed with minimal environmental control. The accelerated corrosion ‘Oddy’ test is frequently used to sift out unsuitable display materials. T the visual assessment is widely recognized to be subjective. the test container has been modified and oxygen depletion appears to give good quantitative measurements of corrosion that correspond with both visual comparison and corrosion loss measurement with linear stripping voltametry or chemical stripping for copper, lead and steel but not for silver.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ПРОЦЕССОВ ТЕПЛООБМЕНА В КОРОВНИКЕ ДЛЯТЕПЛОГО ПЕРИОДА

Annotation. The article presents a mathematical modeling of heat exchange processes in a cowshed with loose animals in the summer period. The considered modeling of heat exchange processes allows us to determine the most rational distribution of sensors that determine the parameters of the microclimate, in particular the air temperature in the cowshed, for effective control of the air temperature, due to the timely inclusion of technical means to ensure the microclimate. Given the large volumes of cowsheds and the lack of special thermal insulation that prevents the maintenance of constant microclimate parameters, an urgent task is to locally maintain the microclimate parameters in the area where the animals are located. For the summer season, fans with a water-evaporative cooling system are accepted by technical means of providing a microclimate that allows reducing the effects of heat stress. For the effective use of local systems for providing microclimate parameters, a rational arrangement of technical means for ensuring the microclimate of the cowshed is necessary, taking into account the dynamic processes of heat exchange. The obtained mathematical model of the dynamics of heat exchange processes in the cowshed in the form of a transfer function allows us to calculate such values of the settings of the air temperature regulators, which ensure high quality control of these processes. The use of a local system for maintaining microclimate parameters based on a forced ventilation device with water-evaporative cooling, taking into account the considered transfer function, allows reducing the air temperature in the cowshed in the warm season in the area where animals are located in the cowshed by 2...8 oC. The use of the proposed ventilation system is advisable at a relative humidity of no more than 65% in the cowshed. At higher relative humidity values, the efficiency of water vapor cooling is significantly reduced.

Influence of hydration/dehydration on adsorbed molecules: Case of phthalate on goethite

The behavior of adsorbed species on metal (hydr)oxides under water unsaturated conditions has been seldom studied despite its major implications in several domains such as geochemistry and heterogeneous catalysis. In this study, chemical forms of phthalate adsorbed on iron hydroxide (goethite) were investigated by infrared spectroscopy upon hydration and dehydration of goethite particle aggregates. Experimental results indicated important changes with relative humidity (RH) on chemical forms of phthalates adsorbed on goethite. With increasing RH from the dried state, bidentate phthalate surface complex is partially desorbed to form a protonated monodentate phthalate complex by using protons from water molecules. This protonated monodentate phthalate is still kept adsorbed on the goethite surface but becomes deprotonated at high RH values by solvating in liquid-like water covering on the goethite surface. DFT calculations made on a simplified system support these adsorption models. These results indicate that further studies are needed on the behavior of adsorbate in water unsaturated systems including hydration/dehydration processes.

Effect of thermal aging on the mechanical performance of timber-timber single-lap adhesive joints

Abstract Timber is a natural material traditionally used in the building industry. In the last decades, developments in scientific research have made timber a high-tech building material. In the field of timber engineering, recent developments concerned advances in the study of adhesive joints and their applications in the field of structures. The growing interest in adhesive joints in timber structures is due to the advantages offered by adhesive technology over traditional mechanical joining techniques. In this paper, the effect of exposure of adhesive joints between timber adherends to high values of temperature and relative humidity is investigated. In particular, two different two-component (2K) epoxy adhesives (EPX1, EPX2) and one polyurethane (PU) in single-lap adhesive joints between mahogany and pine adherends have been used and compared. This research work investigates the possibility of realising new joints between timber adherends in innovative building components (e.g. windows and curtain walls). The results obtained from the experimental campaign showed that PU adhesive has lower mechanical performance than epoxy adhesives, regardless of the aging condition. On the other hand, the epoxy adhesives tested showed high performance and different mechanical behavior after artificial aging.

Diversity of longhorned beetles (Coleoptera: Cerambycidae) in the Caribbean region of Colombia: temporal variation between two fragments of tropical dry forest

Abstract: The tropical dry forest is under constant threat from many anthropic activities which are conducted indiscriminately, modifying the forest, and therefore, affecting species that are closely related to its phenology, such as longhorned beetles (Cerambycidae). The spatio-temporal variation of the cerambycid diversity in two fragments of tropical dry forest (Reserva Campesina la Montaña and La Flecha) in the Caribbean region of Colombia was analyzed. At each locality, four squared plots were delimited, and the beetles were collected with fruit traps, beating sheets and manual capture, and with light traps in the center. Five hundred eighty-seven specimens representing 128 species were collected, of which members of the tribe Ectenessini (Cerambycinae) were the most abundant. At the subfamily level, Cerambycinae was the most abundant (465 specimens) and diverse (73 species), followed by Lamiinae and Prioninae. The highest values of richness (110 species), abundance (428), biomass (21.18 g), and as well as the highest values of true diversity (1D= 73.44, 2D= 34.30) were found during the first precipitations. Regarding beta diversity, temporal variation was determined and mainly explained by a high percentage of turnover (> 70%). Lastly, the high diversity of Cerambycidae was associated with high values of relative humidity and canopy cover during the rainy season. This showed that the structure of the cerambycid community in the tropical dry forest of the Caribbean region of Colombia depends on these variables, which are closely related to precipitation.

Techno-economic comparison of wet and dry cooling systems for combined cycle power plants in different climatic zones

For combined-cycle power plants, the two most dominant steam condenser cooling options are the wet-cooling tower and the air-cooled (dry) systems. The wet cooling system is commonly installed on plants located in areas with available water sources, while the dry system is typically preferred in areas where water is scarce. However, owing to the increasing regulations on water conservation, water usage costs and improvements on cooling system designs, a new approach is required for the optimal selection of plant cooling systems, incorporating site climatic conditions, amongst other considerations. This study presents a comparative techno-economic analysis of a steam turbine cycle with wet- and dry- cooling systems for five typical tropical locations in Nigeria with different climatic conditions and water usage costs. The results show that in the hot (ambient temperatures >33 °C) and dry regions (relative humidity <65%) namely Sahel, Sudan, and Guinea savannah, the plant with wet cooling generated more net power outputs with lower life-cycle costs, operating and maintenance costs than with dry cooling. Thus, for these three regions, the wet cooling system is the best option. But for the Tropical Rainforest and Coastal zones with low ambient temperatures (≤31 °C) and high relative humidity values (≥76%), the performance and cost implications of the plant with dry cooling was more favourable due to lower system sizes and costs requirements. Parametric investigations revealed that high ambient temperature increased the size and costs requirements of air-cooled systems while relative humidity significantly influenced the total power consumption of water-cooled systems.

Climatology of persistent high relative humidity: An example for the Lower Peninsula of Michigan, USA

AbstractThe persistence of high values of relative humidity for several hours to a few days has wide‐ranging implications for natural and human systems. Among its many impacts, persistent high relative humidity contributes to reduced atmospheric visibility, fog frequency and duration, road and powerline icing, the occurrence of foliar plant disease and the temperature at which heat‐related morbidity and mortality can occur. Despite this, the characteristics of humidity spells—including shifts with climate change—are rarely investigated and consequently poorly understood. Hourly relative humidity, precipitation and temperature for 35 locations in the Lower Peninsula (LP) of Michigan during 2003–2017, and for seven locations during 1973–2017, were used to assess, by biweekly periods, spatial, intra‐annual and inter‐annual variations in the characteristics of relative humidity spells. Two humidity thresholds that accommodate a wide range of applications were used: (1) high relative humidity (HRH), defined as hourly values ≥60%, and extremely high relative humidity (EHRH), defined as hourly values ≥85%. Extended HRH and EHRH spells are frequent across the LP, with HRH spells often spanning 36 hr or longer and EHRH spells commonly persisting more than 12 hr. The probability of HRH and EHRH spells generally decreased with time during 1973–2017, particularly later in the period. Although most spells initiate in the late afternoon and early evening hours, this diurnal preference is less evident as spell length increases, especially for EHRH spells. Furthermore, precipitation is more likely to occur with EHRH spells compared to HRH spells. The orientation and strength of spatial gradients in average annual spell frequency are highly dependent on the choice of humidity and duration thresholds and the temperatures accompanying the spells. This study represents the first comprehensive analysis of the persistence of humidity spells and illustrates the potential usefulness of temporally‐flexible climatological summaries relevant for a wide range of applications.

Weather impact on airborne coronavirus survival.

The contribution of this paper toward understanding of airborne coronavirus survival is twofold: We develop new theoretical correlations for the unsteady evaporation of coronavirus (CoV) contaminated saliva droplets. Furthermore, we implement the new correlations in a three-dimensional multiphase Eulerian–Lagrangian computational fluid dynamics solver to study the effects of weather conditions on airborne virus transmission. The new theory introduces a thermal history kernel and provides transient Nusselt (Nu) and Sherwood (Sh) numbers as a function of the Reynolds (Re), Prandtl (Pr), and Schmidt numbers (Sc). For the first time, these new correlations take into account the mixture properties due to the concentration of CoV particles in a saliva droplet. We show that the steady-state relationships induce significant errors and must not be applied in unsteady saliva droplet evaporation. The classical theory introduces substantial deviations in Nu and Sh values when increasing the Reynolds number defined at the droplet scale. The effects of relative humidity, temperature, and wind speed on the transport and viability of CoV in a cloud of airborne saliva droplets are also examined. The results reveal that a significant reduction of virus viability occurs when both high temperature and low relative humidity occur. The droplet cloud’s traveled distance and concentration remain significant at any temperature if the relative humidity is high, which is in contradiction with what was previously believed by many epidemiologists. The above could explain the increase in CoV cases in many crowded cities around the middle of July (e.g., Delhi), where both high temperature and high relative humidity values were recorded one month earlier (during June). Moreover, it creates a crucial alert for the possibility of a second wave of the pandemic in the coming autumn and winter seasons when low temperatures and high wind speeds will increase airborne virus survival and transmission.

Spatial Distribution and Impacts of Aerosols on Clouds Under Meiyu Frontal Weather Background Over Central China Based on Aircraft Observations

AbstractAn airborne field campaign was conducted from 10 June to 10 July 2018 in Hubei Province over central China as a part of the State Key Natural Science Foundation Project referred to as Integrative Monsoon Frontal Rainfall Experiment (IMFRE). Comprehensive observations of atmospheric aerosols and cloud characteristics in this region were collected and analyzed. In this study, data from six flights on nonprecipitating days were selected to investigate the spatial distribution of aerosols and microphysical properties of clouds. The profiles of aerosol number concentrations (Na) were 1 order of magnitude lower than those over the North Plain of China, due to the different atmospheric backgrounds, local emission, and long‐range transport. The highest Na occurred at the altitude of the temperature inversion layer (TIL), indicating that Na profiles were significantly affected by the TIL structure. Relative humidity (RH) had an effect on the aerosol size distribution where high RH values corresponded well with large values of particle mean diameter (MD). Compared with the vertical distributions of Na and MD, their horizontal directions had minor changes, except for the MD at 4,000 m in one case. Of the three flights that penetrated through the stratiform clouds, the probability distribution functions of cloud droplet number concentration (Nc), effective radius (re), and liquid water content (LWC), showed the same features with a single peak mode. Since the nucleation of aerosol in‐cloud caused the decrease of aerosol concentration, the maximum aerosol activation ratio almost reached 74%. The average spectrum of cloud droplets showed a multimodal distribution and their microphysical properties were analyzed in this study.

The Eight Hydrates of Strychnine Sulfate.

Commercial samples of strychnine sulfate were used as the starting material in crystallization experiments accompanied by stability studies. Eight hydrate forms (HyA–HyG), including five novel hydrates, were verified. The crystal structures of HyA (“pentahydrate”) and HyF (“hexahydrate”) were determined from single-crystal X-ray diffraction data. HyF was identified as the most stable hydrate at high water activities at room temperature (RT), and HyA and HyC were also found to be stable at ambient conditions. Long-time storage experiments over nearly two decades confirm that these three hydrates are stable at ambient conditions (20–60% relative humidity). The other five hydrates, HyB (“dihydrate”), HyD, HyE, HyG, and HyH, are only observable at the low(est) relative humidity (RH) levels at RT. Some of these latter forms can only exist within a very narrow RH range and are therefore intermediate phases. By applying a range of complementary experimental techniques such as gravimetric moisture sorption analysis, thermal analysis, moisture controlled PXRD measurements, and variable temperature IR spectroscopy in combination with principal component analysis, it was possible to identify the distinct hydrate phases and elucidate their stability and dehydration pathways. The observed (de)hydration routes, HyA ↔ HyB, HyC ↔ HyD ↔ HyE, HyF ↔ HyG ↔ HyH and HyF → HyA ↔ HyB, depended on the initial hydrate form, particle size, and atmospheric conditions. In addition, a transformation from HyC/HyA to HyF occurs at high RH values at RT. The specific moisture and temperature conditions of none of the applied drying regimes yielded a crystalline water-free form, which highlights the essential role of water molecules for the formation and stability of the crystalline strychnine sulfate phases.

Natural versus synthetic zeolites for controlling the maize weevil (Sitophilus zeamais)–like Messi versus Ronaldo?

Laboratory experiments were carried out to evaluate the impact of zeolites of different origins on the mortality of the maize weevil (Sitophilus zeamais Motschulsky). We tested the efficacy of natural zeolites (Slovenian and Serbian) and a synthetic zeolite (Asorbio®). Diatomaceous earth (SilicoSec®) was used as a positive control. We applied the zeolites as surface treatments (at concentrations of 10 g/m2 and 20 g/m2) and as admixtures (grain with zeolites) (at concentrations of 450 ppm and 900 ppm). The mortality of the weevils when the zeolites were applied as a surface treatment was evaluated every day until the 7th day after application; delayed mortality was measured every day until the 14th day after application. When the zeolites were admixed, we evaluated mortality after the 7, 14, and 21 days. The research was performed at two different relative humidity values (55 and 75%) and at three different temperatures (15, 20 and 25 °C). We conclude that the mortality of maize weevils was influenced by relatively high temperature and low relative humidity values. There was no impact of the zeolite dose on the mortality of the maize weevils when applied as a surface treatment. The mortality of the weevils was similar in the treatments with the two natural zeolites (Slovenian and Serbian), while the mortality of the maize weevils was the lowest in the treatments with Asorbio®. The use of natural zeolites as a protectant for stored products was shown to be effective in our research, although additional surveys should be conducted.