Moisture Time Research Articles

Understanding the Corrosion Behaviour of Steel Under Alternate Oil/Water Wetting with Different Oil Viscosities

The corrosion behaviour of steel under alternate wetting conditions with various oil viscosities was investigated by an “alternate wetting cell,” combined with electrochemistry measurements, contact angle measurements, and molecular dynamics simulation. Under static conditions, corrosion was mitigated more efficiently with an increase of viscosity, because a large static friction force between high-viscosity oil and the steel surface prolongs the oil film lifetime and oil wetting time. Under dynamic conditions, the effect of oil viscosity on the corrosion and wetting behaviour of carbon steel was not dominated in comparison to that of the static conditions.

Investigation of the influence of cell compression after winding on electrolyte wettability based on experiments and lattice Boltzmann simulation

The wetting of the active materials in a lithium-ion battery cell after electrolyte filling is a time-critical process in the manufacturing of lithium-ion batteries. The exact influencing factors on wetting are the subject of experimental investigations and numerical simulations. The dominant wetting at the material transitions, depending on the material’s compression caused by the cell winding, has not yet been examined. Therefore, this publication investigates the effects of material compression during the winding process on wettability through experiments and lattice Boltzmann simulations. The results show and quantify accelerated wetting caused in the material transitions compared to single electrode wetting, attributed to larger pores and higher permeability. Increasing compression in inner windings of cylindrical cells shows smaller pores sizes and reduced permeability, leading to a decelerated wetting behavior. Considering permeability and evaporation is essential for the mathematical replication of the wetting phenomena. With these findings, the total wetting time of a winding in a cylindrical 21700 cell can be estimated between 816 s to 1198 s.

FARKLI SÜPER DAĞITICILARIN KETOPROFEN İÇEREN AĞIZDA DAĞILAN TABLETLERİN İN VİTRO KARAKTERİZASYON PARAMETRELERİ ÜZERİNDEKİ ETKİSİNİN DEĞERLENDİRİLMESİ

Objective: Orally Disintegrating Tablets (ODTs) have revolutionized pharmaceutical drug delivery, offering a patient-friendly alternative for those struggling with conventional tablet swallowing. This study delves into the impact of superdisintegrants (crospovidone, sodium starch glycolate, and croscarmellose sodium) on the in vitro characterization of Ketoprofen-containing ODTs. ODTs are designed to rapidly disintegrate in the oral cavity without water, enhancing patient compliance, ensuring faster therapeutic onset, and providing convenience. Material and Method: The micromeritic properties of pre-compression Ketoprofen ODT blends were assessed for bulk density, tapped density, Hausner ratio, and compressibility index. ODTs were formulated using a direct compression method to maintain component uniformity. Comprehensive characterization included weight variation, tablet hardness, friability, wetting time, and in vitro disintegration time assessments. The drug content was determined through UV spectrophotometry of dissolved ODTs, and dissolution studies were conducted in pH 6.8 phosphate buffer using USP apparatus XXIV. Result and Discussion: Results showed uniform tablet mass and favorable powder mixture flowability, ensuring ODT physical properties. Tablets exhibited excellent mechanical resistance with consistent hardness and low friability loss. All formulations demonstrated high and uniform drug content. Different superdisintegrants influenced wetting, disintegration, and dissolution times. Crospovidone exhibited the fastest wetting time but longer disintegration times, attributed to increased tablet hardness. Dissolution studies revealed that crospovidone-containing ODTs had faster drug release compared to croscarmellose sodium and sodium starch glycolate, aligning with literature findings. The study emphasized the importance of considering both wetting and disintegration times for a comprehensive evaluation of ODT performance. Croscarmellose sodium and sodium starch glycolate hindered drug release, forming gel-like masses impeding dissolution, while crospovidone enhanced drug release in formulated ODTs. In conclusion, the study provides valuable insights for pharmaceutical development and patient-centric drug delivery solutions, showcasing the influence of superdisintegrants on ODT performance and emphasizing the importance of considering various parameters for comprehensive evaluation.

Assessment of the Arc Resistance of 3D-Printed Insulation Materials for Outdoor High-Voltage Applications

High-voltage electrical equipment insulation often uses composite materials like epoxy resin, cross-linked polyethylene, polyurethane, and silicone rubber as encapsulation. 3D printing technology offers a more efficient and cost-effective solution, producing intricate elements without cutting and casting. Research shows that 3D printed materials have comparable properties to polymer-based insulation, but further testing is needed to evaluate their resistance to harsh environmental conditions. This research investigates the arc resistance properties of 3D printed insulation materials for outdoor high-voltage applications, assessing their suitability for outdoor applications. The wet and dry arc resistance tests were performed in accordance with ASTM D495-99 and IEC-60587. The present work investigated three varieties of samples: polylactic acid, epoxy resin, and silicone rubber. The results of the tests reveal that polylactic acid test samples have average wet and dry arc resistance times of 2.5 hours and 1.4 seconds, which is less than silicone rubber and epoxy resin. Additional research is required to comprehend the behavior of arc formation in polylactic acid insulation materials for high-voltage 3D printing applications.

Implementation of Quality by Design approach for Development of Optimized Drug Delivery System of Antidepressant Drug

The work presented aimed to implement of “Quality by Design” (QbD) approach to develop optimized fast dissolving tablet (FDT) of Fluoxentine. A face centered Central composite design was employed to develop optimized dosage form. FDTs were prepared by direct compression followed using sublimation technique with additive effect of super disintegrants. Impact of independent variables such as concentration of super-disintegrant and sublimating agent was determined on dependent variables i.e. wetting time, disintegration time and drug release. Data optimization was done by developing validation check batches as well as overlay plot developed by statistical software. Optimized formulation shows 18.08 s wetting time (WT), 19.84 s disintegration time (DT) and the drug release was found to be 85.82 % in 5 m. The accelerated stability studies for optimized FDTs shows no significant changes during one month stability studies. In conclusion, the optimized fast dissolving tablets for Fluoxentine was successfully developed employing by QbD approach with least utilization of man, money and efforts.

Mixing approach for 3D printable concrete: method of optimisation of superplasticiser dosage

This study is a systematic investigation of superplasticiser (SP) addition methods and optimum SP dosage with various water-to-binder ratios (w/b) for mixing three-dimensional printable concrete. In this study, five distinct strategies were adopted to arrive at the optimum method of addition. In the first strategy, a random mixing approach was applied to identify, through visual observation, methods for adding SP with varying time patterns. Secondly, a constant time pattern was adopted from the random approach for mixing and the optimal SP dosage was determined. In the third strategy, different methods of adding the optimum SP dosage were examined. In the fourth strategy, the batching effect of the material with the optimum SP dosage was assessed. Finally, the printable regions with different values of w/b and SP dosages were correlated. It was observed that the optimum SP dosage, in the range of 0.10–0.21% of binder, with w/b = 0.21–0.25 achieved adequate printability parameters by full addition of SP following a constant wet mixing time as the optimal application. However, after applying the optimum SP dosage, a supplemental SP dosage is required at appropriate intervals to retain the workability for higher batches.

Phthalate esters pollution in the leachate, soil, and water around a landfill near the sea, Iran

This investigation aimed to scrutinize the level of phthalate esters (PEs) in the landfill leachate of a coastal city in the north of the Persian Gulf and the sensitive ecosystem (soil and water) around it. Soil (two depths) and water samples were prepared from 5 stations in wet and dry seasons. The studied landfill leachate contained 114–303 μg/L of phthalates. The highest concentration of phthalates was related to bis (2-ethylhexyl) phthalate (3257 ng/g) in the wet season at surface soil (0–5 cm) in the landfill site, while the lowest one (6 ng/g) belonged to dimethyl phthalate at sub-surface soil at 700 m from the landfill in the dry season. A significant change in the level of Σ6PEs in the dry (303 μg/L) and wet (114 μg/L) seasons (P ≤ 0.05) was observed for water samples. The PE concentrations in wet times were higher in all soil depths than in dry times. With increasing depth, the content of phthalates decreased in all studied environments. A direct relationship was observed between the phthalates concentration and the pH value of leachate/water and soil. The PEs concentration was linked to electrical conductivity (leachate: R2 = 0.65, P < 0.01 and surface soil: R2 = 0.77, P < 0.05) and the soil organic content. The ecological risk of di-n-butyl phthalate, benzyl butyl phthalate, bis (2-ethylhexyl) phthalate, and di-n-octyl phthalate in the wet season was greater than one. The results showed that significant levels of phthalate esters are released from landfills to the surrounding environment, which requires adequate measures to maintain the health of the ecosystem and nearby residents.

Evaluating wet and dry contact time of contaminated produce with chlorine solution against Listeria monocytogenes and Salmonella enterica

Chlorine is the most widely used sanitizer, however, there are varying reports on the exposure time and its effectiveness on fresh produce. This study determined the minimum exposure time for wet and dry contact chlorine treatments with the highest efficacy in reducing Listeria monocytogenes and Salmonella enterica on spinach and bell pepper surfaces. The chlorine wash at 100 mg/L for 1 min resulted in a significant reduction (p < 0.05) of both pathogens on both produce. S. enterica was reduced by 4.86 log CFU/g on spinach and by 3.97 log CFU/g on bell pepper, while L. monocytogenes was reduced by 3.7 log CFU/g on spinach and by 3.08 log CFU/g on bell pepper. The majority of Listeria cross-contamination (>2.30 log CFU/g) on un-inoculated spinach and bell peppers was observed within 1 min of chlorine washing. Cross-contamination of Salmonella on spinach was >2.9 log CFU/g within 1 min and the level increased to 4.21 log CFU/g after 6 min. This study showed that washing spinach and bell pepper for up to 6 min with a 100 mg/L chlorine solution did not achieve additional reductions in L. monocytogenes and S. enterica populations compared to a 1 min wash.

Water Evaporation CFD Method with the Meshfree Volume-Volume-Coupling Approach for Wet Automotive Component Dry-Out Time Prediction

Water Evaporation CFD Method with the Meshfree Volume-Volume-Coupling Approach for Wet Automotive Component Dry-Out Time Prediction

Effect of Dimethyl Sulfoxide Primer on Microtensile Bond Strength and Micromorphological Pattern of HEMA-free Universal Adhesive to Dry/Wet Dentin After Thermomechanical Aging.

To evaluate the effect of dimethyl sulfoxide (DMSO) primer on microtensile bond strength (μTBS) and the micromorphological pattern of a hydroxyethyl methacrylate (HEMA)-free universal adhesive (UA) applied on wet/dry dentin in etch and rinse (E&R) mode before/after thermomechanical aging. For the μTBS test, the mid-coronal dentin of 80 human mandibular first molars was exposed and etched with 35% phosphoric acid. Teeth were randomly divided into two equal groups: dry and wet dentin (n = 40). Then, each group was subdivided according to dentin pretreatment by DMSO before UA (Gluma Bond Universal, Heraeus Kulzer, Hanau, Germany) application into unpretreated and 10% DMSO/water (OT Primer S100, OT Oy Dent, Turku, Finland) pretreated (n = 20). Resin composite blocks were built up using a specially designed Teflon mold. In every subgroup, both the μTBS test and failure analysis by stereomicroscope were evaluated immediately after 24 h and after thermomechanical aging (n = 10). The data were statistically analyzed using a three-way analysis of variance (ANOVA) (p = 0.05). For the micromorphological pattern, 16 maxillary first premolars were distributed as mentioned in the μTBS test, prepared, and buccolingually sectioned. The dentin-resin interface was examined using an environmental scanning electron microscope (ESEM) (n = 2). Three-way ANOVA revealed that the main effects and interactions between dentin wetness, dentin pretreatment, and evaluation time (thermomechanical aging) were not significant for µTBS (p> 0.05). Adhesive failure was the predominant type in all immediate and delayed specimens. Longer and more prominent resin tags were observed at dentin-resin interfaces after DMSO application. Neither the initial dentin wetness condition, dentin pretreatment, nor thermomechanical aging could affect the dentin bond strength. No correlation was found between the bond strength and the micromorphology findings. Key words:Wet/dry dentin bonding, Microtensile bond strength, Micromorphology, Universal adhesive, Dimethyl sulfoxide, Thermomechanical aging.

Natural Mucilage From Phoenix dactylifera L. as an Alternative for Artificial Saliva

The sensation of dry mouth is a clinical illness known as xerostomia. Treatment is necessary for alleviating symptoms in patients who experience either transient or persistent dry mouth. It is essential to develop artificial saliva for this purpose. The fruit of the Phoenix dactylifera is edible and has been used in food. Its mucilage from dried fruits was extracted by soaking in distilled water and precipitated with 90% v/v ethanol. The mucilage of P. dactylifera was used for producing artificial saliva and was combined with other components including proteins and electrolytes. The translucent light brown gel solution was seen in the artificial saliva using P. dactylifera mucilage. The measured relative density ranged from 1.02 to 1.15 g/mL. Artificial saliva had to become more viscous with the addition of P. dactylifera mucilage and its concentration. Their pH values ranged between 6.98 and 7.15. The produced artificial saliva had a wetting time ranging from 7.53 to 9.70 min, which is similar to the typical human saliva. Artificial saliva could form a film in the mouth after certain periods. It was found that artificial saliva exhibited many adsorption bands corresponding to various biomolecules, such as protein, carbohydrate, and lipid, and had a unique peak at 275 nm. The results of this investigation suggest that a formulation including mucilage from P. dactylifera may be utilized to treat xerostomia patients by temporarily lubricating and hydrating their mouths when they experience persistent dry mouth.

Holistic modeling of the electrolyte filling process to study the dosing and wetting behavior of lithium-ion batteries

The electrolyte filling process of lithium-ion batteries is characterized by extensive wetting times and significant costs for experimental process design, which is becoming increasingly relevant in the current landscape of fast-evolving cell designs to optimize energy density. In this study, an approach for applying computational fluid dynamics to simulate the flow of liquid electrolyte through the battery void volume and porous cell stack is shown. Results of the simulation on pore scale are used to calculate the permeability of the cell stack, which provides an input parameter for the simulation on cell scale. On a cell scale, the calculated parameters act as a resistance value of the cell stack, enabling the modeling of the interaction between dosing and wetting. The detailed model setup including simulation parameters is provided, so that cell manufacturers and researchers will be able to set up individual simulation models to predict the filling behavior during cell development.

Deterioration mechanism of loess from Ili valley region of China under wet and dry cycles: evidences from shear tests

The properties of loess in the Ili region of China are significantly affected by repeated cycles of rainfall and evaporation. It is thus essential to investigate the deterioration mechanism of loess subjected to the wet and dry cycles. This paper employs various methods, including the direct shear and triaxial shear tests, as well as the scanning electron microscopy (SEM), to evaluate the variation patterns of shear strength parameters and microstructure of Ili loess. The direct shear test was conducted on loess samples experiencing a limited number of wet and dry cycles (0, 1, 3, 5, 7, and 9), while the triaxial shear test focused on a more extensive range of wet and dry cycles (0, 1, 3, 10, 20, and 30). In parallel, the alterations in the shear strength parameters of the loess material under different shear tests were also scrutinized. The findings obtained from this research revealed that the shear strength of Ili loess decreased to varying degrees based on the two test methods when they are affected by the wet and dry cycles. Comparing the results with the same number of wet and dry times (0, 1 and 3 times), both the shear strength and cohesion obtained from the triaxial shear test were greater than those from the direct shear test, while the results for the angle of internal friction were reversed. Moreover, the scanning electron microscope tests on Ili loess did indicate that the micro-particle size, pore space, morphology, soil structure, and particle contact mode exhibited the deterioration with different degrees. The micro-structural change is believed to be the main reason for the deterioration mechanism of the shear strength. The research outcomes will enrich the understanding about the loess properties in Central Asia, providing data reference and theoretical basis for engineering construction in these region.

Spatiotemporal patterns of net primary productivity of subtropical forests in China and its response to drought

Net primary productivity (NPP) is an important indicator used to evaluate the carbon sequestration capacity of forest ecosystems. Subtropical forest ecosystems play an indispensable role in maintaining the global carbon balance, while frequently occurring drought events in recent years have seriously damaged their productivity. However, the spatiotemporal patterns of NPP, as well as its response to drought, remain uncertain. In this study, the multiscale drought characteristics in subtropical China during 1981–2015 were analyzed based on the standardized precipitation evapotranspiration index. Then, simulated and analyzed the spatiotemporal NPP of subtropical forests by the boreal ecosystem productivity simulator model. Finally, the response of NPP to drought was analyzed based on multiple statistical indices. The results show that most regions in subtropical China experienced mild and moderate drought during 1981–2015. In particular, the extent of drought severity has shown a noticeable increasing trend after 2000. The forest NPP ranged from 622.64 to 1323.82 gC·m−2·a−1, with an overall increase rate of 16.15 gC·m−2·a−1; in particular, the contribution of the western forest NPP became increasingly important. Drought stress has limited the growth of subtropical forest NPP in China, with summer and wet season time scales of drought having the greatest impact on forest NPP anomalies, followed by autumn time scales. The limitation is mostly because the drought duration continually increased, leading to differences in the impact of drought on forest NPP before and after 2000, with declines of 59.55 % and 82.45 %, respectively, mainly concentrated in southwestern regions, such as Yunnan, Guangxi, and Sichuan provinces. This study quantitatively analyzed the impact of drought on subtropical forest NPP, and provides scientific basis for subtropical forest response and adaptation to climate change.

PLM4Alg: Protein Language Model-Based Predictors for Allergenic Proteins and Peptides.

The rising prevalence of allergy demands efficient and accurate bioinformatic tools to expedite allergen identification and risk assessment while also reducing wet experiment expenses and time. Recently, pretrained protein language models (pLMs) have successfully predicted protein structure and function. However, to our best knowledge, they have not been used for predicting allergenic proteins/peptides. Therefore, this study aims to develop robust models for allergenic protein/peptide prediction using five pLMs of varying sizes and systematically assess their performance through fine-tuning with a convolutional neural network. The developed pLM4Alg models have achieved state-of-the-art performance with accuracy, Matthews correlation coefficient, and area under the curve scoring 93.4-95.1%, 0.869-0.902, and 0.981-0.990, respectively. Moreover, pLM4Alg is the first model capable of handling prediction tasks involving residue-missed sequences and sequences containing nonstandard amino acid residues. To facilitate easy access, a user-friendly web server (https://f6wxpfd3sh.us-east-1.awsapprunner.com) has been established. pLM4Alg is expected to become the leading machine learning-based prediction model for allergenic peptides and proteins. Its collaboration with other predictors holds great promise for accelerating allergy research.

Evaluation of Low- and Intermediate-Temperature Cracking Performance of Fiber-Reinforced Asphalt Mixtures

This study was conducted to assess the impact of aramid fiber reinforcement on the fatigue and thermal cracking performance of asphalt mixtures at intermediate and low temperatures, respectively. The study also involved evaluating the experimental consistency and ranking fiber-reinforced asphalt mixtures (FRAMs) based on their performance. One aggregate (diabase stone), one binder type (PG 76-22), and two combinations of aramid fibers, added at different dosages, were used to produce three FRAMs. These fibers included polyolefin/aramid (PFA) fibers at 0.05% dosage by mix weight and Sasobit-coated aramid (SCA) fibers at 0.01% and 0.02% dosages. An unreinforced (control) mix was also produced without any reinforcement. All mixtures were produced at a batch plant by keeping their binder content constant (at 5.5%). The manufacturer recommended dry and wet mixing times were used for better fiber distribution and represent actual mixing conditions. The laboratory performance of plant-produced FRAMs was assessed to characterize the low- and intermediate-temperature cracking performance. The indirect tension asphalt cracking test, semi-circular bend test, three-point bending beam tests, and uniaxial fatigue tests were performed at intermediate temperature; the disk shape compact tension test and thermal stress restrained specimen test tests were performed at low temperature. Fibers were successful at improving the fatigue cracking of asphalt mixtures based on intermediate-temperature testing results. In addition, fiber reinforcement, regardless of dosage and combination, showed improvements in low-temperature (thermal) cracking performance. Furthermore, based on ranking analysis for selected performance indicators from each experiment, the SCA 0.02% reinforced mix on average showed the highest cracking resistance.

A Review of User Perceptions of Drought Indices and Indicators Used in the Diverse Climates of North America

Drought monitoring and early detection have improved greatly in recent decades through the development and refinement of numerous indices and indicators. However, a lack of guidance, based on user experience, exists as to which drought-monitoring tools are most appropriate in a given location. This review paper summarizes the results of targeted user engagement and the published literature to improve the understanding of drought across North America and to enhance the utility of drought-monitoring tools. Workshops and surveys were used to assess and make general conclusions about the perceived performance of drought indicators, indices and impact information used for monitoring drought in the five main Köppen climate types (Tropical, Temperate, Continental, Polar Tundra, Dry) found across Canada, Mexico, and the United States. In Tropical, humid Temperate, and southerly Continental climates, droughts are perceived to be more short-term (less than 6 months) in duration rather than long-term (more than 6 months). In Polar Tundra climates, Dry climates, Temperate climates with dry warm seasons, and northerly Continental climates, droughts are perceived to be more long-term than short-term. In general, agricultural and hydrological droughts were considered to be the most important drought types. Drought impacts related to agriculture, water supply, ecosystem, and human health were rated to be of greatest importance. Users identified the most effective indices and indicators for monitoring drought across North America to be the U.S. Drought Monitor (USDM) and Standardized Precipitation Index (SPI) (or another measure of precipitation anomaly), followed by the Normalized Difference Vegetation Index (NDVI) (or another satellite-observed vegetation index), temperature anomalies, crop status, soil moisture, streamflow, reservoir storage, water use (demand), and reported drought impacts. Users also noted the importance of indices that measure evapotranspiration, evaporative demand, and snow water content. Drought indices and indicators were generally thought to perform equally well across seasons in Tropical and colder Continental climates, but their performance was perceived to vary seasonally in Dry, Temperate, Polar Tundra, and warmer Continental climates, with improved performance during warm and wet times of the year. The drought indices and indicators, in general, were not perceived to perform equally well across geographies. This review paper provides guidance on when (time of year) and where (climate zone) the more popular drought indices and indicators should be used. The paper concludes by noting the importance of understanding how drought, its impacts, and its indicators are changing over time as the climate warms and by recommending ways to strengthen the use of indices and indicators in drought decision making.

Theoretical modeling of key parameters of wet film in roll coating process of coating panel

The purpose of this dissertation is to quantitatively regulate the wet film thickness of coating panels in metal packaging during roll coating, which has not been accomplished in previous studies. The aim of the research is to derive a formula model for the roll coating machine, which is a general-purpose equipment, to provide theoretical support for quantitatively regulating wet film thickness and calculating leveling time. Based on the coating leveling formula studied by Orchard [Appl. Sci. Res. 11, 451 (1963)], combined with the working conditions of the roll coating process, an innovative application of boundary slip theory and Hertzian theory is used to analyze the functional relationship of each parameter in the roll coating process, and to construct a model of wet film leveling time. The process data were obtained from factory equipment. The validation of the formula model refers to the method adopted by Wang and others, who processed experimental fixtures with different wavelengths and crest heights to experimentally validate the model. The average thickness of the wet film and the leveling time are the key to the roller coating process. The average wet film thickness is the key parameter affecting the quality of the product, and the leveling time determines when the wet film enters the dry film process. The wet film thickness mainly depends on the pressure of each roll in the roll coating process. The wet film leveling time model accurately constructs the functional relationship between process parameters, leveling time, and wet film thickness, which can be quantitatively calculated. The leveling time model is experimentally verified to be correct.

Prediction Model of Residual Soil Shear Strength under Dry–Wet Cycles and Its Uncertainty

Granite residual soil is widely distributed in Southeast Fujian. Large-scale engineering construction leads to the exposure of residual soil slopes to the natural environment. Affected by seasonal climate factors, the soil of slopes experiences a dry–wet cycle for a long time. The repeated changes in water content seriously affect the shear strength of soil, and then affect the stability of the slope. In order to explore the influence of the dry–wet cycle on the shear strength of granite residual soil in Fujian, an indoor dry–wet cycle simulation test was carried out for shallow granite residual soil on a slope in Fuzhou, and the relationship between water content, dry–wet cycle times, and the shear strength index, including the cohesion and internal friction angle of the granite residual soil, was discussed. The results show that when the number of dry–wet cycles is constant, the cohesion and internal friction angle of the granite residual soil decrease with an increase in water content. The relationship between the cohesion, internal friction angle, and water content can be described using a power function. Meanwhile, the fitting parameters of the power function are also a function of the number of wet and dry cycles. The prediction formulas of the cohesion and internal friction angle considering the number of dry–wet cycles and water content are established, and then the prediction formula of shear strength is obtained. The ratio of the predicted value of shear strength to the test value shall be within ±15%. An error transfer analysis based on the point estimation method shows that the overall uncertainty of the predicted value of shear strength caused by the combined uncertainty of the predicted value of cohesion and the internal friction angle and the single-variable uncertainty of the predicted value of shear strength caused only by the uncertainty of the predicted value of either the cohesion or internal friction angle increases first and then decreases with an increase in the number of dry–wet cycles. All increase with an increasing water content. The maximum standard deviation of the proposed shear strength prediction model of granite residual soil is less than 9%.

Warming decreases desert ecosystem functioning by altering biocrusts in drylands

Abstract Warming and precipitation fluctuations are changing desert ecosystems in global drylands. However, the effects of climate change on keystone species such as cryptogamic biocrust in drylands remain relatively under‐investigated, even though biocrusts play a vital role in desert ecosystems. We conducted a long‐term experiment (14 years) to simulate the responses of two main types of biocrusts to warming coupled with reduction in precipitation that was achieved by open‐top chambers (OTCs) to simulate the predicted warming and precipitation decreasing under climate change scenario. We also conduct a structural analysis to evaluate the resulting changes in desert ecosystem functioning (carbon and nitrogen cycling). Neither warming and corresponding rainfall reduction treatments had a negative effect on lichen species richness, but both treatments reduced lichen cover and biomass. The negative effects of warming on moss‐dominated crusts were much greater than those on lichen‐dominated crusts. Although mosses and lichens had varying degree responses to warming, the loss of mosses and decreased lichen cover and biomass, as well as the shortening of the wet time, resulted in a reduction in carbon and nitrogen fixation, soil enzyme activity and water‐holding capacity of biocrusts and topsoil. These impacts collectively change the water balance of drylands and weaken the hydrological and biogeochemical function of biocrusts. Synthesis and applications: Results from this long‐term experiment suggest that the ecosystem C and N cycling and water balance of global drylands may be highly impacted by climate change, in part because of the response of biocrusts, which contribute an important implication for both dryland restoration and earth system dynamics.