Simulated Rain Research Articles

Feasibility of Genipin to Evaluate Chitosan Rainfastness for Biopesticide Applications

Chitosan’s effectiveness as an antimicrobial coating for biocontrol depends on its resistance to rain. Unfortunately, to the best of our knowledge, there is currently no satisfactory method for assessing this resistance, which means that field tests have to be carried out to evaluate it in situ, which are difficult to implement and therefore unsuitable for optimizing formulations. This article explores the use of genipin to detect residual chitosan on surfaces after simulated rain, using fluorescence microscopy. A first study on real vine leaves using MacroFluo microscopy was carried out but showed limitations for the intended application, notably due to the requirement for high chitosan concentrations to achieve detectable signals. A semi-quantitative method based on confocal laser scanning microscopy was then developed on model leaves, as real leaves were unsuitable due to their autofluorescence. Among the tested models, Parafilm® proved to be the most effective, showing sufficient fluorescence after reaction with genipin, even at low chitosan concentrations. For the first time, a method that does not require chromophore grafting onto chitosan has been proposed, allowing for the comparison of chitosan solution rainfastness under laboratory conditions. As an application, the effect of the counter ion on chitosan’s rain resistance was evaluated.

Determination of water retention by the native field of the Pampa Biome with simulated rain

The Pampa was one of the most neglected biomes in Brazil, mainly due to its floristic composition distinct from the others. The expansion of agriculture and forestry are often linked to the advancement of negative impacts on the hydrology of this biome. However, there isn't enough information about the hydrological functioning of small basins with native vegetation in Pampa. The objective of this study is to evaluate the applicability of two different methodologies to determine water retention by native vegetation of the Pampa Biome, using a rainfall simulator. The methodology 1 used structured samples of native field vegetation and soil, and methodology 2 used only vegetation samples without the presence of soil; all of which were submitted to the application of simulated rain. With the obtained data, the amount of water that this vegetation retains during rainy events was estimated. Using method 1, we found estimated retention values of 5.4% and 10.9%, 18.6% and 27.8%. However, through method 2 we found estimated retention values of 8.5% and 12.7%. In any case, both methods showed significant values of water retention by this vegetation, being the variations found associated with the methodology itself, or the natural characteristics of each study area.

Determination of water retention by the native field of the Pampa Biome with simulated rain

Pampa was one of the most neglected biomes in Brazil, mainly due to its floristic composition distinct from the others. The expansion of agriculture and forestry are often linked to the advancement of negative impacts on the hydrology of this biome. However, there isn't enough information about the hydrological functioning of small basins with native vegetation in Pampa. The objective of this study is to evaluate the applicability of two different methodologies to determine water retention by native vegetation of the Pampa Biome, using a rainfall simulator. The methodology 1 used structured samples of native field vegetation and soil, and methodology 2 used only vegetation samples without the presence of soil; all of which were submitted to the application of simulated rain. With the obtained data, the amount of water that this vegetation retains during rainy events was estimated. Using method 1, we found estimated retention values of 5.4% and 10.9%, 18.6% and 27.8%. However, through method 2 we found estimated retention values of 8.5% and 12.7%. In any case, both methods showed significant values of water retention by this vegetation, being the variations found associated with the methodology itself, or the natural characteristics of each study area.

HYDRAULIC DYNAMICS OF THE REGOLITHIC NEOSOL IN THE CERRADO OF THE SERRA DA CANASTRA NATIONAL PARK-MG

The knowledge of soil water dynamics, as elements are added, removed, and transformed, is an aid to understanding the processes at play in landscapes. Understanding the functioning of natural environments not only contributes to comprehending the natural dynamics of systems but also serves as a reference for adopting measures in areas at different stages of degradation. In this sense, this study sought to analyze the physical/hydraulic characteristics of the Regolithic Neosol in the Serra da Canastra National Park, MG. For this purpose, two different models of field infiltrators were used: namely a rain simulator and a concentric ring infiltrometer. Results involving the use of a rain simulator indicated high soil infiltration capacity (99.31%) even when subjected to high-intensity events (57.4 mm/h). The ring infiltrometer revealed high values of basic infiltration velocity (317.58 mm/h). These values indicate that despite being shallow (20 cm), the soil, characterized by coarse material (sand and lateritic gravel), has a high capacity to incorporate water precipitated into the profile, generating subsurface lateral flows between the higher and lower parts of the slope and causing the movement of iron along with underground water flow.

Evaluating sorbents for reducing per- and polyfluoroalkyl substance mobility in biosolids-amended soil columns.

Sustainable reuse of biosolids as fertilizers is being threatened by the presence of per- and polyfluoroalkyl substances (PFAS) in our waste stream warranting research on strategies that will minimize PFAS mobility from land-applied biosolids. Here, we evaluated the ability of waste-derived sorbents aluminum chlorohydrate water treatment residuals (ACH-WTRs, 1wt%) and biosolids-based biochar (1.5wt%) to reduce mobility of PFAS in columns with 3wt% biosolids-amended soils with and without sorbent layered on top of soil only and operated under transient unsaturated conditions. Cycles of simulated rain events of approximately three pore volumes distributed over a 4-day period followed by 3 days of drying were imposed for 6 months. Total PFAS concentrations in collected leachates were lower in the sorbent-treated columns compared to the control columns. Biochar outperformed the ACH-WTR with 41% versus 32% lower total PFAS in leachate, respectively, compared to the control. The most significant mitigation effect was observed with PFOS (perfluorooctane sulfonate) with 68% and 62% less PFOS in the leachates from the columns treated with ACH-WTR or biochar compared to the control, respectively. These results provide a first-of-its-kind assessment of the potential benefit of co-applying WTRs or biochar with biosolids to reduce PFAS mobility in biosolids-amended soils.

Domed nests do not offer additional environmental protection in some songbirds

Abstract Nest architecture in birds is highly variable ranging from simple scrapes through to elaborate woven constructions. In species that nest in open situations the nest can have a cup open to the elements or the nest has a dome positioned over the cup. The functional properties of domed nests have yet to be explored and this study compared the thermal insulation and rainproofing properties of nests built by four species of European songbird, two of which build domed nests whereas the others build open cup nests. Insulatory values were recorded using temperature loggers. Nests were exposed to a simulated rain event and the amount of water absorbed and the minutes for the nest to dry were determined. The nests were then deconstructed into their component parts. Materials used to build the nests differed among the species. Differences in thermal insulation were associated with the species and the size of the nest. The amount of water absorbed by a nest during a simulated rainfall event was negatively associated with the size of the nest. Feathers and moss had significant positive effects on thermal insulation and rainproofing, respectively. There was no significant difference between domed and open nests in terms of thermal insulation or rainproofing, except for the time taken for a nest to dry, which showed a significant interaction between nest mass and type of nest. Insulatory values and degree of rainproofing were like data from previous reports for songbird nests of comparable size. That no differences observed between domed and open cup nests in the species studied may reflect similarity among species, although it may be due to a paucity of data from a wider range of species building domed nests.

A comparative study of foliar particulate matter wash-off from plants under natural and simulated rain conditions

Urban greening can reduce concentrations of particulate matter (PM). However, most of the PM is deposited temporarily on foliage and can be removed by precipitation. Due to the unpredictability and randomness of natural rain and the complexity of environmental conditions, the effect of rainfall on PM removal from foliage is usually examined using simulated rain. The aim of this study was to compare the effects of natural and simulated rain on washing off PM deposited on the foliage of seventeen plant species (evergreen/deciduous trees and shrubs, herbaceous plants). Regardless of the PM fraction studied, simulated rain washed off a larger fraction of the PM than natural rain. A novel finding is the differential role played by various plant characteristics in determining the effectiveness of PM wash off under natural and simulated rain conditions, with their influence being more pronounced under natural rainfall. The type of rainfall and PM size fraction influenced the effectiveness of the PM wash-off from different plant groups. Natural rain was more effective at removing PM from evergreen trees, while simulated rainfall was more effective at removing PM from deciduous shrubs and herbaceous plants. The results obtained from this study suggest that simulated rain does not reflect the effects of natural precipitation on the processes removing PM from leaves, and therefore should not be used to explain phenomena that occur in realistic conditions.

DINÂMICA HÍDRICA DO SOLO DE FITOFISIONOMIA DE CERRADO RALO DO CHAPADÃO DO DIAMANTE - SERRA DA CANASTRA (MG)

The Cerrado is characterized as an important Brazilian biome, forming strategic hydrographic basins within its territory that are significant both nationally and internationally. Despite its importance, the biome has been increasingly impacted by anthropogenic activities. In this context, this study aims to analyze and understand the physical-hydraulic characteristics of the soil in a sparse Cerrado physiognomy located in the Chapadão do Diamante (Serra da Canastra-MG), providing the necessary foundation for the assessment and development of future management strategies for similar areas. For field data prospecting, a rain simulator and a concentric ring infiltrometer were used. The results demonstrated a high infiltration capacity in the study area, with no significant surface runoff even under high-intensity precipitation (57.35 mm), revealing high values of basic infiltration velocity (BIV) at 626.56 mm/h. Overall, these values are associated with the dynamics of landscape elements, emphasizing the importance of biological processes, such as the role of vegetation and soil fauna, in modulating the soil's ability to retain, infiltrate, and store water. Keywords: Water Infiltration; Rain Simulator; Concentric Ring Infiltrometer.

Effects of geographical location and size on the functional properties of harvest mouse Micromys minutus nests in Great Britain

AbstractNest construction is a feature of a range of taxa, yet the functional properties of nests are poorly understood. Avian nests offer thermal insulation, structural support and protection from rain, but to date there are few studies that have explored these functions for mammal nests. Here nests constructed by harvest mice (Micromys minutus) were studied ex situ to determine the thermal insulation provided by the nest wall and the degree to which simulated rainfall was absorbed. Nests were collected from across Great Britain and analysis explored whether nest size and geographical location affected insulation or rainproofing. Nests were constructed from grass leaves woven into an outer wall that surrounded smaller pieces of grass that filled the interior of the nest. Nest mass was positively related to thermal insulation but unrelated to geographical location. By contrast, nest mass was positively related to the amount of water nest absorbed after simulated rain but volume and longitude were inversely related to the time it took the nest to dry out. In many ways, harvest mice nests had similar functional properties to those of small songbirds, i.e., to provide thermal insulation and rainproofing. This study was the first to explore the environmental protection potentially offered to harvest mice by their nests. The study has highlighted our poor understanding of the factors that determine the function of mammal nests. There is scope for more research into the functional properties, e.g., thermal insulation or rainproofing, of a wide variety of mammal nests.

Green buffer areas and green roofs: performance design to improve the urban water cycle

Abstract While in all Europe the land use does not decrease – contrary to EU soil strategy that would actualize the zero net land use by 2050 – cities are plagued by problems such as air pollution, urban heat island effect and uncontrolled run-off following intense rain events, which degrade the environment threatening the health and the safety of inhabitants. The impermeable materials and are responsible for the worsening of the urban water cycle and, at the same time, for the increase in summer air temperatures: both those effects can be mitigated by nature-based and draining solutions. The paper explains the hydrological phenomena of the urban impervious surfaces, highlighting the typical functional defects, providing then a list of various green technologies suitable to overcome the common issues of city centers like high density / reduced spaces, irreversible impervious surfaces, undersized drainage, presence of sub-structures / sub-systems, conservation of architectural heritage. The technical green solutions on the ground (bio-retention systems, rain gardens, trees, pervious pavements…) and on the roofs, specifically designed, behave 1) as a buffer for the stormwater and superficial run-off, being able to collect water, 2) as providers of side effects that can affect water quality, biodiversity, amenity in cities. Experimental results from a rain simulation are presented in order to argue potentials and limitations of these solutions, often narrated as salvific, or, on the contrary, underestimated in their technological specificities.

Characterization of Silica Sand-Based Pervious Bricks and Their Performance under Stormwater Treatment

The acceleration of urbanization has disrupted natural water cycles, resulting in increased impervious urban surfaces and non-point source pollution from stormwater runoff. Addressing urban stormwater recharge has become crucial. This study introduces a novel silica sand-based permeable filtration material, investigating its surface characteristics, pore structure, permeability, and pollutant interception capabilities. The results demonstrate that hydrophilic binder coating modification of the permeable surface sand aggregate, combined with hydrophilic inorganic additives, having a porous structure with an average pore size of less than 50 μm and a porosity between 15% and 35%, significantly enhances surface hydrophilicity, achieving a permeation rate of up to 6.8 mL/(min·cm²). Moreover, it shows exceptional filtration and anti-clogging properties, achieving over 98% suspended solids interception and strong resistance to fouling. Dynamic biofilm formation experiments using simulated rain and domestic wastewater explore biofilm morphology and function on silica sand filtration well surfaces. Mature biofilms sustain COD removal efficiency exceeding 70%, with levels consistently below 50 mg/L, NH4+ decreasing to 2 mg N/L, and total nitrogen maintained below 10 mg N/L. The system features anoxic, anoxic, and aerobic zones, fostering synergistic organic matter and nitrogen removal by diverse microorganisms, enhancing pollutant mitigation. Silica sand-based permeable filtration material effectively mitigates urban stormwater runoff pollutants—suspended solids, organic matter, and nitrogen—offering an innovative solution for sponge city development and rainwater resource management.

Improving the Gaussianity of radar reflectivity departures between observations and simulations using symmetric rain rates

Abstract. Given that the Gaussianity of the observation error distribution is the fundamental principle of some data assimilation and machine learning algorithms, the error structure of radar reflectivity has become increasingly important with the development of high-resolution forecasts and nowcasts of convective systems. This study examines the error distribution of radar reflectivity and discusses what causes the non-Gaussian error distribution using 6-month observations minus backgrounds (OmBs) of composites of vertical maximum reflectivity (CVMRs) in mountainous and hilly areas. By following the symmetric error model in all-sky satellite radiance assimilation, we reveal the error structure of CVMRs as a function of symmetric rain rates, which is the average of the observed and simulated rain rates. Unlike satellite radiance, the error structure of CVMRs shows a sharper slope for light precipitation than for moderate precipitation. Thus, a three-piecewise fitting function is more suitable for CVMRs. The probability density functions of OmBs normalized by symmetric rain rates become more Gaussian than the probability density functions normalized by all samples. Moreover, the possibility of using a third-party predictor to construct the symmetric error model is also discussed in this study. The result shows that the Gaussian distribution of OmBs can be further improved via more accurate precipitation observations. According to the Jensen–Shannon divergence, a more linear predictor, the logarithmic transformation of the rain rate, can provide the most Gaussian error distribution in comparison with other predictors.

The Addition of Pore Holes in Paving Blocks in an Effort to Increase Infiltration

The problem of waterlogging and surface runoff on impermeable pavement surfaces requires finding new ways to manage water flow, especially from rainwater. The type of permeable pavement that is often used is paving block. The use of paving blocks for pavement materials is expected to reduce puddles that occur after rain. One way is to modify the paving block to be greater in seeping water into the soil. This study aims to determine the extent to which the effect of adding pore holes in paving block can increase water infiltration in surrounding soil. This research was conducted through testing in the Laboratory. The type of research is quantitative with experimental method using a rain simulator tool with variations of paving block. From the research results obtained that the addition of pores in the paving block affects the infiltration that occurs. This is evidenced by the increae in the value of infiltration, the infiltration rate value of normal paving block is 182.92-10.43 mm/hour, 2% ratio is 183.75-10.75 mm/hour, 5% ratio is 190.00-11.30 mm/hour, 7% ratio is 231.33-11.46 mm/hour, 10% ratio is 236.88-17.61 mm/hour. From the test results between pore holes with infiltration rate has a significant relationship of 0.037 (<0,05).

Temporal Variation Pattern of Runoff and Surface Sediment and Piping Erosion in Silt Loam Soil under Different Slopes Using Artificial Rain Simulator

Temporal Variation Pattern of Runoff and Surface Sediment and Piping Erosion in Silt Loam Soil under Different Slopes Using Artificial Rain Simulator

Weathering Tests on Raw and Consolidated Vicenza Stone.

The preservation of cultural heritage, particularly historical stone structures, represents a very challenging matter due to several environmental and anthropogenic factors. Vicenza stone, a calcareous rock known for its historical significance and widespread use in architectural masterpieces, requires significant attention for conservation. In fact, as the demand for sustainable and effective preservation methods intensifies, the exploration of innovative consolidation strategies becomes essential. To this end, inorganic consolidants, based on alkaline silicate formulations and nano-silica, were explored for their promising performance in enhancing the surface properties and chemical stability of Vicenza stone. In particular, the durability of treated and untreated Vicenza stone samples was evaluated by means of accelerated weathering tests such as freeze-thaw cycles, salt crystallization and simulation of acid rain. The experimental results revealed that Vicenza stone is very resistant to the effects of freeze-thaw cycles and acid rain; both the accelerated weathering tests did not show significant differences between treated and untreated VS samples. A different behavior was detected for the test for resistance to salt crystallization, whose findings led us to deduce that, for this kind of degradation, it is possible to observe a more beneficial effect of the consolidation treatments on the stone durability.

Granulation compared to co-application of biochar plus mineral fertilizer and its impacts on crop growth and nutrient leaching

Mechanized biochar field application remains challenging due to biochar’s poor flowability and bulk density. Granulation of biochar with fertilizer provides a product ready for application with well-established machinery. However, it’s unknown whether granulated biochar-based fertilizers (gBBF) are as effective as co-application of non-granulated biochar with fertilizer. Here, we compared a gBBF with a mineral compound fertilizer (control), and with a non-granulated biochar that was co-applied at a rate of 1.1 t ha−1 with the fertilizer in a white cabbage greenhouse pot trial. Half the pots received heavy rain simulation treatments to investigate nutrient leaching. Crop yields were not significantly increased by biochar without leaching compared to the control. With leaching, cabbage yield increased with gBBF and biochar-co-application by 14% (p > 0.05) and 34% (p < 0.05), respectively. Nitrogen leaching was reduced by 26–35% with both biochar amendments. Biochar significantly reduced potassium, magnesium, and sulfur leaching. Most nitrogen associated with gBBF was released during the trial and the granulated biochar regained its microporosity. Enriching fertilizers with biochar by granulation or co-application can improve crop yields and decrease nutrient leaching. While the gBBF yielded less biomass compared to biochar co-application, improved mechanized field application after granulation could facilitate the implementation of biochar application in agriculture.

Towards Sustainability: An Eco-Friendly Approach for Durable Anti-Icing Superhydrophobic Surfaces.

The growing interest in flexible superhydrophobic surfaces extends beyond various practical applications like solar panels, flexible electronics, etc. This study introduces a cost-effective and environmentally friendly method to create a durable, flexible, and optically semi-transparent superhydrophobic film with an extreme anti-icing character. The prestrained polydimethylsiloxane film subjected to biofuel-based flame treatment under controlled conditions induces microwrinkles with a superimposed cluster of nanoparticles while maintaining surface flexibility and transparency. This meticulous process enhances surface roughness, achieving superhydrophobic characteristics (θ > 165˚) with a remarkably low tilting angle (<3˚) with adhesion against water <2µN (lower than Lotus leaf). The films applied over solar panels result in <1% voltage drop within 5s due to effective cleaning under simulated rain. The remarkable anti-icing performance of the developed film is characterized by ice adhesion <25kPa over 50 icing/de-icing cycles attributed to the presence of nanoclusters. The films displayed exceptional resilience and sustained efficacy under prolonged exposure to harsh external environments. These superhydrophobic films, characterized by flexibility, durability, and transparency, present promising opportunities for fabricating structures, even with intricate geometries. These findings imply a significant stride in the practical utilization of superhydrophobic surfaces, demonstrating their potential in diverse real-world applications.

A complete environmental wind tunnel for studying the evolution of snow accumulations under the effects of wind, rain, and heat

A complete environmental wind tunnel for studying the evolution of snow accumulations under the effects of wind, rain, and heat

Soil hydro-physical variables and crop residues determinate runoff, soil loss, and glyphosate and AMPA concentration in the aqueous phase under simulated rainfall events.

Soil structural degradation and water erosion processes were observed even in no-tillage schemes in the Pampas region. Within these conservation systems, agrochemical application per hectare is one of the highest globally. Thus, this entails a serious risk of water contamination. The objectives of this study were to (1) test the hypothesis that the hydrological dynamics and sediment concentration related to surface runoff were conditioned by soil structure regardless of the presence of maize (Zea mays L.) crop residue and (2) assess the incidence of maize crop residue on glyphosate and aminomethylphosphonic acid (AMPA) concentration in runoff. The soil under study corresponded to Arroyo Dulce Series (Typic Argiudoll silty loam soil). Rain simulations were performed in the laboratory on undisturbed soil samples. Total runoff and infiltration rate were similar between treatments with C(+) and without C(-) maize crop residues (C(+) 1381.40mL and 14.27mm h-1, C(-): 1529.70mL and 21.67mm h-1). The C(-) treatments showed a higher sediment concentration than C(+) (1.58 and 0.42g 100mL-1, respectively). Glyphosate and AMPA average values in runoff were 15.9 and 33.9µg L-1. High variability of the hydro-physical properties and occurrence of soil structure, particularly platy ones, were detected. The hydrological variables were conditioned mainly by the occurrence of platy structures regardless of crop residue presence. Glyphosate concentration was increased in the first runoff event by the presence of corn residues, while AMPA concentrations were higher in the second runoff event in both residue treatments. In this study, maize residue on the soil surface protected the soil from sediment detachment but did not change runoff or infiltration. Thus, the implementation of agricultural management practices that promote vegetative residue cover has shown positive results to erosion.

Development of a Device for Monitoring Erosion in the Field.

Monitoring erosion is an important part of understanding the causes of this geotechnical and geological phenomenon. In order to monitor them, it is necessary to develop equipment that is sophisticated enough to resist the sun and water without damage, that is self-mechanized, and that can support the amount of data collected. This article introduces a rain-triggered field erosion monitoring device composed of three main modules: control, capture, and sensing. The control module comprises both hardware and firmware with embedded software. The capture module integrates a camera for recording, while the sensing module includes rain sensors. By filming experimental soil samples under simulated rain events, the device demonstrated satisfactory performance in terms of activation and deactivation programming times, daytime image quality without artificial lighting, and equipment protection. The great differences about this monitoring device are its ease of use, low cost, and the quality it offers. These results suggest its potential effectiveness in capturing the progression of field erosive processes.