Effect Of Water Storage Research Articles

Characteristics of Nitrogen Distribution and Influencing Factors in A Reservoir of Henan Province

In order to reveal the spatial and temporal distribution characteristics of nitrogen and its influencing factors in a reservoir in Henan Province, a study on the changing characteristics of nitrogen in the water body was carried out in the fall of 2019 and the summer and fall of 2020 to identify the main sources of pollution in the water body in the reservoir area. The results showed that the total nitrogen concentration in the water body ranged from 1.65 to 3.53 mg/L, which exceeded the eutrophication threshold of the water body. Among them, the nitrogen component was dominated by nitrate nitrogen, which accounted for 62.63% of the total nitrogen, mainly from runoff pollution and endogenous release. On a seasonal scale, nitrogen concentrations exhibited higher concentrations in the fall than in the summer. At the spatial scale, total nitrogen, nitrate nitrogen and organic nitrogen concentrations showed similar trends, with a gradual decrease from the upstream to the front of the dam, and an increase after the dam, which was related to the dilution of the water body and the effect of the reservoir's water storage on sand retention. Principal component analysis showed that the key factors affecting water quality in the reservoir were pH, water temperature and ammonia. Pearson correlation analysis showed that the spatial and temporal characteristics of reservoir nitrogen were related to environmental factors, material transport transformations and anthropogenic influences.

Stochastic Flow Analysis for Optimization of the Operationality in Run-of-River Hydroelectric Plants in Mountain Areas

The highly temporal variability of the hydrological response in Mediterranean areas affects the operation of hydropower systems, especially in run-of-river (RoR) plants located in mountainous areas. Here, the water flow regime strongly determines failure, defined as no operating days due to inflows below the minimum operating flow. A Bayesian dynamics stochastic model was developed with statistical modeling of both rainfall as the forcing agent and water inflows to the plants as the dependent variable using two approaches—parametric adjustments and non-parametric methods. Failure frequency analysis and its related operationality, along with their uncertainty associated with different time scales, were performed through 250 Monte Carlo stochastic replications of a 20-year period of daily rainfall. Finally, a scenario analysis was performed, including the effects of 3 and 30 days of water storage in a plant loading chamber to minimize the plant’s dependence on the river’s flow. The approach was applied to a mini-hydropower RoR plant in Poqueira (Southern Spain), located in a semi-arid Mediterranean alpine area. The results reveal that the influence of snow had greater operationality in the spring months when snowmelt was outstanding, with a 25% probability of having fewer than 2 days of failure in May and April, as opposed to 12 days in the winter months. Moreover, the effect of water storage was greater between June and November, when rainfall events are scarce, and snowmelt has almost finished with operationality levels of 0.04–0.74 for 15 days of failure without storage, which increased to 0.1–0.87 with 3 days of storage. The methodology proposed constitutes a simple and useful tool to assess uncertainty in the operationality of RoR plants in Mediterranean mountainous areas where rainfall constitutes the main source of uncertainty in river flows.

A modified Xin'anjiang model and its application for considering the regulatory and storage effects of small-scale water storage structures

To improve flood prediction accuracy in the basin, this paper constructs a modified Xin'anjiang (M-XAJ) model to account for the regulatory and storage effects of small-scale water storage structures on surface runoff, based on the original Xin'anjiang (XAJ) model. In the M-XAJ model, the regulatory and storage effects of small water storage are calculated by utilizing an aggregated reservoir using multi-bottom sills graded weir flow pattern (MBSP). The discharge processes of the aggregated reservoir is combined with the processes of runoff production and convergence over the natural area to form the overall discharge processes at the outlet section. Using the two subbasins of the Xianghongdian Reservoir as case studies, 13 flood events were selected to validate the predictive capabilities of the M-XAJ model. The results indicate that (1) the qualification rate for flood peak (Qp) and the qualification rate flood volume (Qv) substantially increased for the two sub-basins during the training and verification periods. Additionally, the mean relative error of peak lag time (MEtp) was considerably reduced. Specifically, the mean Nash efficiency coefficient (MNS) for floods at the Qingshan section improved by 0.18 and 0.24 respectively. (2) the M-XAJ model improved prediction accuracy for the first flood event following an extended drought period without rainfall, as well as for the initial flood preceding a sequence of flooding events. However, the prediction accuracy for continuous flooding events was not noticeably enhanced by the M-XAJ model. (3) the M-XAJ model demonstrated improved simulation capabilities for low- and moderate-magnitude flood events; however, there were no noticeable enhancements for high-magnitude flooding simulations.

Effects of Different Water Storage and Fertilizer Retention Substrates on Growth, Yield and Quality of Strawberry

To address the problems of inadequate water and fertilizer retention performance of the substrate, which results in the waste of water and fertilizer resources and then contributes to existing agricultural non-point source pollution, this study selected raw materials with different water retention performances for substrate compounding and explored their water retention performance and impact on the growth, yield and quality of strawberries. The experimental setup utilized the strawberry cultivar ‘Hongyan’ as the test subject and incorporated different proportions of vermicompost, coconut bran, biochar and humic acid into the organic fertilizer. A total of 12 treatment groups were formed across three gradients, involving different proportions of vermicompost with 0.05, 0.10 and 0.15 proportions of coconut bran/biochar and 0.05, 0.15 and 0.20 proportions of humic acid. To evaluate the water retention performance, uniform water and fertilizer regulations were applied. The results revealed that the treatment groups T4 (vermicompost:coconut bran = 0.5:0.1) and T5 (vermicompost:biochar = 0.5:0.1) exhibited higher water absorption multiplicity, lower water infiltration rates, and better water retention performances, but there was no significant difference between the two treatment groups. Among them, T4 could effectively improve the nutrient content of the substrate, and the substrate nitrogen-use efficiency (NUE) increased by 5.80% compared with CK2. Also, plant total nitrogen (TN) and total phosphorus (TP) uptake increased by 81.18% and 4.74%, respectively, compared with CK2, which in turn promoted the growth and development of the plant and improved the fruit yield and quality to a certain extent. Meanwhile, T4 had the highest urease and catalase activities, with sucrase activity ranking second only to T1. In contrast, T5 demonstrated greater effectiveness in improving the average fruit weight and maximum fruit weight, registering increases of 22.98% and 36.22% compared to CK2, respectively, but the effect on the total yield was less pronounced. A comprehensive evaluation of strawberry growth found that the T4 treatment was superior. In conclusion, the ratio of vermicompost and coconut bran at 0.5:0.1 improved and promoted the substrate water retention performance and strawberry growth.

Forecast sugarcane maturity from agrometeorological data and soil water storage

The environment (climate and soil) can stimulate the accumulation of sugars in the cane, inducing the plant´s maturation process. In this way, we can estimate sugarcane maturity based on the crop's growth response to environmental conditions, which allows us to quantify the raw material (ethanol or sugar) and plan the harvest. The aim of this study was to evaluate the effects of agrometeorological variables and soil water storage on the sugarcane maturation process and to generate forecasting models for soluble solids content (°Brix) and total recoverable sugars (TRS, kg t-1). The experiment was carried out in the Santo Antonio de Goiás, Brazil. We evaluated °Brix and TRS of the sugarcane cycles (cane-plant, 1st ratoon, 2nd ratoon). The agrometeorological data was obtained from a weather station, which made it possible to calculate the crop’s water balance and degree-day. All the variables were subjected to multivariate statistical analysis, which selected the most significant variables. The models used degree-days, reference evapotranspiration and soil water storage as independent variables, which obtained multiple coefficients of determination (R_p^2) greater than 0.60. The estimates showed a good fit for both °Brix and TRS models, which determined a mean absolute error (MAE) of 1.15 °Brix and 9.88 kg t-1, respectively; and very good confidence index (c > 0.75). Independent estimates obtained MAE < 2.60 ºBrix, while TRS resulted in MAE < 21.30 kg t 1, with “c” ranging from good to optimum (c > 0.70). Models based on multivariate analysis can be used to estimate the sugarcane harvest point based on the sugar content in the stalks, agrometeorological variables and soil water storage.

The effect of water storage on nanoindentation creep of various CAD-CAM composite blocks

BackgroundTo study the effect of water storage (3 months) on the creep deformation of various CAD-CAM composite structures at the nanoscale and compare it to that at the macroscale.MethodsSeven CAD-CAM blocks were investigated: five resin-composite blocks (RCB), one polymer-infiltrated ceramic network (PICN) block, and one ceramic-filled polyetheretherketone (PEEK) block. Specimens of each material (n = 6) were separated into two groups (n = 3) according to their storage conditions (24 h dry storage at 23˚C and 3 months storage in 37˚C distilled water). Nano-indentation creep measurements were undertaken (creep depth measured in µm) using a nanoindenter (Nanovea) equipped with Berkovich three-sided pyramidal diamond tip. The machine was set for the chosen parameters: a load of 20 gf, a pause of 20 s, and the material type. Thirty indentations on 3 samples were made for each material for each test. Data were analysed using two-way ANOVA followed by one-way ANOVA and Bonferroni post hoc tests and independent t-test (< 0.05) for comparisons between the materials.ResultsThe nanoindentation creep depth after 24 h storage ranged from 0.09 to 0.33 μm and increased after 3 months storage in distilled water to between 0.28 and 3.46 μm. There was a statistically significant difference in nanoindentation creep behaviour between the two storage conditions for each investigated material (independent t-test) and between all materials (Bonferroni post hoc). There was a non-significant negative correlation between nanoindentation creep (µm) and filler weight% at 24 h dry storage but a significant correlation at 3 months of water storage. A further non-significant positive correlation between nanoindentation creep (µm) and bulk compressive creep (%) was found.ConclusionThe PICN material showed superior dimensional stability in terms of nanoindentation creep depth in both storage conditions. Other composite blocks showed comparable performance at 24 h dry condition, but an increased nanoindentation creep upon water storage.

Effects of Snow Water Storage on Hydrologic Partitioning Across the Mountainous, Western United States

AbstractIn the montane western United States, where the majority of downstream water resources are derived from snowmelt, a warming climate threatens the timing and amount of future water availability. It is expected that the fraction of precipitation falling as snow will continue decreasing and the timing of snowmelt will continue shifting earlier in the year with unknown impacts on partitioning between evapotranspiration and streamflow. To assess this, we employ a Snow Storage Index (SSI) to represent the annual temporal phase difference between daily precipitation and daily modeled surface water inputs (SWI, the sum of rainfall and snowmelt), weighted by the respective amounts. We coupled the SSI metric with a Budyko‐based framework to determine the effect of snow water storage on relative hydrologic partitioning across snow‐influenced watersheds in the western U.S. Greater snow water storage was positively correlated with greater hydrologic partitioning to streamflow, particularly in the North Cascades/Cascades (r2: 0.62), Blue Mountains (r2: 0.56), Canadian Rockies (r2: 0.55), Idaho Batholith, (r2: 0.48), and Columbia Mountains/Northern Rockies (r2: 0.45). The weekly SWI:P ratio was an equally strong predictor for hydrologic partitioning, particularly in mid‐spring (e.g., March/April) in the same mountainous areas (r2: 0.62–0.74, across the same eco‐regions). The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If SSI decreases with future warming, the volume of water partitioned streamflow will decrease non‐uniformly across the western U.S. with substantial implications for ecosystems and agricultural, industrial, and domestic water supplies.

Water use strategy determines the effectiveness of internal water storage for trees growing in biofilters subject to repeated droughts

Impervious surfaces create large volumes of stormwater which degrades receiving waterways. Incorporating trees into biofilters can increase evapotranspiration and therefore reduce stormwater runoff. Tree species with i) high water use, ii) drought tolerance and iii) rapid and full recovery after drought have been suggested for biofilters to maximise runoff reduction while minimising drought stress. Moisture availability fluctuates greatly in biofilter substrates and trees growing in biofilters will likely experience multiple, extended drought events that increase trade-offs between these traits. Providing an internal water storage has the potential to reduce tree drought stress and increase evapotranspiration. Two urban tree species (Agonis flexuosa and Callistemon viminalis) were grown in plastic drums with biofilter profiles. Three irrigation treatments were used: well-watered, drought with an internal water storage and drought without an internal water storage. Transpiration, leaf water potential and biomass were measured to determine the effect of biofilter internal water storage and repeated drought events on tree water use, drought stress and growth. Biofilter internal water storage improved water use and reduced drought stress for A. flexuosa, whereas C. viminalis reduced leaf loss but saw no change in water use or drought stress. A. flexuosa with biofilter internal water storage was able to recover transpiration to well-watered levels after repeated droughts, while C. viminalis experienced reduced recovery ability. It is recommended all biofilters planted with trees should have internal water storage. In systems with lower moisture availability a species with more stomatal control, such as A. flexuosa, is recommended. If selecting a species with less stomatal control, such as C. viminalis, the internal water storage volume needs to be increased to avoid drought stress.

The effect of water storage and humidity on the incidence of dengue hemorrhagic fever in the work area of the Kebayakan Health Center, Central Aceh Regency

Background: Dengue Hemorrhagic Fever (DHF) is an acute febrile disease found in the tropics with a geographic distribution like malaria. Dengue fever is spread to humans by the Aedes aegypti mosquito. More than 100 tropical and subtropical countries have experienced dengue eruptions and dengue hemorrhagic fever; approximately 50,000 cases each year are hospitalized, with thousands of people dying. Objective: This study aims to determine the effect of water storage and humidity on the incidence of Dengue Hemorrhagic Fever (DHF) in the work area of the Kebayakan Health Centre, Central Aceh Regency. Materials and Methods: This research is an analytic survey research with a case-control research design. In this case, there were 55 DHF patients consisting of children and the elderly as respondents. Controls were 55 DHF patients consisting of children and the elderly. The analysis used a chi-square test. Result: The results showed that the factors that significantly affected the incidence of DHF were humidity (P=0.002 OR=4.571 95% CI=1.752-11928) and water reservoirs (P=0.004 OR=3.328 95% CI=1.521–7.282). Conclusions: it is hoped that the community will participate in efforts to eradicate dengue hemorrhagic fever (PSN-DHF), and water reservoirs should be cleaned at least once a week to prevent the presence of mosquito larvae and pay more attention to environmental sanitation.

Mechanical Stability of Self-Adhesive/Ion-Releasing Resin Composites

The purpose of this study was to assess the effects of water storage on the surface microhardness (VHN) and fracture toughness (K1C) of two self-adhesive restorative materials compared to traditional resin composite and resin-modified glass ionomer cement (RMGIC) restorative materials. Methods: Two self-adhesive materials (Activa and Vertise Flow), a nonflowable composite (Filtek Z250), and an RMGIC (Fuji II) were evaluated. Hardness measurements (n = 12) were recorded at three time intervals: (i) one-hour post-irradiation; (ii) after one day of storage in water at 37 °C; and (iii) after 90 days of storage in water at 37 °C. Fracture toughness (K1C) measurements (n = 12) were conducted after one day of storage in water at 37 °C and 90 days of storage in water at 37 °C. ANOVA and Tukey post hoc tests were used for statistical analysis. Results: Baseline VHN data were 38.2–58.3, decreasing significantly to 28.8–55.6 following 90 days of water storage. The Filtek Z250 had the highest VHN before and after storage, while the Activa had the lowest. KIC values varied between 0.98–1.32 MPa·m0.5. The highest value was for the Filtek Z250 while the Fuji II showed the lowest value (after both 1 and 90 days of storage in water). However, KIC values decreased significantly after storage, except for the Fuji II. Conclusion: Self-adhesive/ion-releasing resin composites were negatively affected by water storage. Material reinforcements are possible future areas to explore.

Effect of Water Storage on Repair Bond Strength of Resin-Based Composite to Different Restorative Materials

Effect of Water Storage on Repair Bond Strength of Resin-Based Composite to Different Restorative Materials

Effect of Water Storage and Bleaching on Light Transmission Properties and Translucency of Nanofilled Flowable Composite.

This study investigated the effect of water sorption and bleaching on light transmission properties (Straight-light transmission (G0), Light diffusion (DF) and Amount of transmitted light (AV)) and translucency parameters (TP) of nano-filled flowable composites. A total of 35 composite disks (0.5 mm thickness) were prepared using A2 shade of 5 nanofiller composites (n = 7/each); Beautifil Flow Plus X F03 (SHOFU INC), Clearfil Majesty ES Flow (Kuraray Noritake Dental), Estelite Universal Flow (EUF, Tokuyama Dental), Estelite Flow Quick (Tokuyama Dental) and Filtek Supreme Ultra Flowable Restorative (FSU, 3M ESPE). Then, they were cured by LEDs (VALO, Ultradent) on standard mood (1000 mW/cm2) for 20 s. Samples were tested for straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV) and (TP) immediately after 24 h (dry storage), after 1-week water storage and after each of the three cycles of in-office bleaching (HiLite, SHOFU INC). Result: G0, DF, AV and TP were significantly affected by different materials (p < 0.001). The AV of FSU increased significantly after the 1-week water storage, then after the second bleaching cycle (p < 0.001). The TP for EUF slightly decreased (p = 0.019) after 1-week water storage, then increased throughout bleaching. Conclusion: Ageing/bleaching conditions do not affect G0, DF, AV and TP. The compositional variation between nano-filler composites resulted in a significant difference between materials.

Effects of Water Storage and Demand on Hydrological Drought Propagation in Upstream and Downstream Areas

Effects of Water Storage and Demand on Hydrological Drought Propagation in Upstream and Downstream Areas

Baobabs at the edge: 90-year dynamics of climate variability, growth, resilience, and evolutionary legacy effects

Climate variability and resilience remain gaps in tree research, challenged by the interacting factors in climate change, long-term resilience and the influence of evolutionary legacy effects. In a multidisciplinary approach using 90-year (1930–2020) climate-growth data, we investigated the dynamics of climate variability on growth and resilience of the tropical African baobab (Adansonia digitata) at the range edge in climate-variable, southeast Africa. The main driver of climate variability, ENSO (El Niño-Southern Oscillation), triggered 83% of droughts exacerbated by positive Indian Ocean Dipole (pIOD) events. Growth over 90 years was positively correlated with maximum temperature and increased after the 1976–1977 Global Warming Shift. The influence of warming was compromised by climate variability and extreme events. Although growth is a measure of adaptive capacity, accelerated growth over the past 20 years contrasted with dehydration, canopy dieback and a novel Didymella pathogen. Resilience was contingent on high genetic diversity (polyploidy and heterozygosity) and Neotropical legacy effects of stem water storage and longevity trade-offs of low growth, recruitment and reproduction. The evolution of resprouting in disturbed, fire-prone ecosystems and bark regeneration increased recovery from disturbance. As resource opportunists, baobabs adopted a fast-slow survival strategy. Rainfall and warming enhanced growth while low and variable rainfall favoured a conservative, low growth-higher survival strategy. Low rainfall, climate extremes and topography increased mortality risk. Mortality was higher at lower elevations on site and regionally. Low growth may conserve the baobab in climate warming but the southern hemisphere tropics is one of two identified global hotspots with amplified hot years. The heightened disturbance predicted from increased climate variability, hot droughts and landfalling tropical cyclones magnifies mortality risk for “Africa’s favourite tree.”

Effects of UV Aging, Water Storage and Recycling on Mechanical Properties of Biogenic Wood‐Plastic Composites from Polyamide 11

AbstractIn this study, the weather stability of a biogenic wood‐plastic composite (bio‐WPC) made of bio‐based polyamide 11 (PA11) and 30 wt% of beech wood particles (BP) by twin‐screw compounding is evaluated. It is found that UV aging has no significant effects on the modulus of elasticity and tensile strength of the injection molded bio‐WPC due to the UV stabilization of the PA11. It is also found that the water absorbed by the hydrophilic beech wood particles and by the PA11 matrix during water storage acts as a plasticizer and results in a decrease in stiffness and strength as well as an increase in the elongation at break. The second focus of this study is the evaluation of the mechanical properties after recycling. It is found that recycling leads to a reduction of the modulus of elasticity and tensile strength by 18% respectively 19%, compared to the original bio‐WPC. These effects are attributed to a mechanical and thermo‐oxidative degradation of the beech wood particles but also of the PA11 through recycling by granulation and repeated injection molding. A corresponding drop in stiffness and strength is typical for recycled composite materials. Overall, the recycled bio‐WPC therefore has a good level of mechanical properties after recycling.

Complex Class II Bulk-Fill Resin Composite Restoration: Cuspal Deflection and Effect of Water Storage on Microleakage: A Laboratory Study

Complex Class II Bulk-Fill Resin Composite Restoration: Cuspal Deflection and Effect of Water Storage on Microleakage: A Laboratory Study

Regional ultimate tensile strength and water sorption/solubility of bulk-fill and conventional resin composites: The effect of long-term water storage.

The effect of long-term water storage on the regional ultimate tensile strength (UTS), water sorption (Wsp) and water solubility (Wsl) of conventional and bulk-fill resin composites at various depths was investigated. Composite specimens light-cured from one side were sectioned into beams corresponding to different depths (1-5 mm) and stored in water for 24 h, 1 week, 1 month, 6 months or 1 year. UTS increased during the first week and then gradually decreased over time, especially in deeper regions. Bulk-fill composites initially exhibited similar UTS at all depths, whereas the UTS of conventional composites at 1 mm and 5 mm differed significantly at all time points. Wsp and Wsl increased with depth and storage time, markedly at 3-5 mm after 1 month for conventional composites and after 6 months for bulk-fill composites. The signs of degradation at depths beyond 3 mm suggested that even bulk-fill composites have suboptimal properties in layers more than 3 mm in thickness.

A Continental Assessment of Reservoir Storage and Water Availability in South America

This study presents the first continental assessment of water storage and its influence on the availability of water of the river systems of South America. Although hydraulic infrastructure has the potential to cause several impacts on river systems and the environment, their relevance in water resources systems is irrefutable. The human services that dams and reservoirs provide to society, e.g., hydroelectricity, water supply, irrigation, or flood control, are vital services that society requires to develop. Despite this fact, the interactions of dams and reservoirs in the river systems of South America have not been explored from a hydrological perspective. In this study, we present the first assessment of the potential effects of water storage at a basin scale in South America. For this purpose, first we present an analysis of the current conditions and the influence of water storage in the basins of the continent. Then, we estimate the potential water availability of each basin, to evaluate the role of water storage in the availability of water in the continent. Our findings indicate that the ‘Colorado’ and ‘Negro’ basins in Argentina are the most influenced by water storage in the continent. Moreover, our results suggest that reservoirs improve the potential water availability capacity, particularly in the southern basins of the continent. With this study, we expect to provide helpful insights about the current interactions of reservoirs with the river systems of the continent.

Effect of Water Storage on Hardness and Interfacial Strength of Resin Composite Luting Agents Bonded to Surface-Treated Monolithic Zirconia.

Background: Durable bonding between resin composite luting agents (CLA) and zirconia is still a matter of controversy. The purpose of this study was to evaluate the effect of water storage on hardness and interfacial strength of three CLA, a non-adhesive (Multilink Automix/ML), an adhesive (Panavia F 2.0/PF) and a self-adhesive (PermaCem 2.0/PC), bonded to polished (CL) and grit-blasted (AL: 50 μm alumina, SJ: Sil-Jet + Monobond Plus silane) monolithic zirconia surfaces. Methods: CLA specimens (n = 5/cement, condition) were prepared, stored under dry conditions or immersed in water, and Vickers hardness (VH) measurements were obtained at 1 h, 24 h, 1 week and 3 weeks intervals. Optical profilometry was used to determine the roughness parameters (Sa, Sz, Sdr, Sci) of zirconia surfaces (n = 5/treatment). A shear strength test (SBS, n = 10 × 2/cement) was performed to assess the strength and fractography of the cements bonded to zirconia after isothermal water storage and thermal-cycling (TC). Results: PF demonstrated significantly lower VHN after water storage at all time intervals, PC at 1 w, 3 w and ML at 3 w. SJ and AL showed significantly higher values from CL in all roughness parameters. Weibull analysis revealed the following significance in σο ranking within the same material: AL, SJ, ALTC > SJTC, CL > CLTC (PF); SJ, SJTC, AL, ALTC > CL, CLTC (PC) and SJ, SJTC > AL > ALTC > CL, CLTC (ML). Within the same surface treatment subgroups, the significance in σo ranking was PC, ML > PF (before/after TC) for SJ; PC > PF > ML (before TC), PC, PF > ML (after TC) for AL, and PC > PF > ML (before/after TC) for CL. For the m ranking, the only significant difference within each material group was found in PC (AL > ALTC) and for the same surface treatment in AL (PC > ML). Conclusion: There are significant differences in the water plasticization susceptibility of the CLA tested; the materials with adhesive monomers were the most affected. Tribo-chemical silica coating combined with a silane coupling agent was the most efficient bonding treatment for the non-adhesive and the self-adhesive materials. The adhesive CLA performed better on alumina-blasted than on tribo-chemically coated surfaces.

Mechanical degradation of contemporary CAD/CAM resin composite materials after water ageing

ObjectiveThe aim of the present study was to assess the effect of water storage on the quasi-static properties and cyclic fatigue behavior of four contemporary CAD/CAM resin composite materials. MethodsThe CAD/CAM resin composites Grandio Blocs, LavaTM Ultimate, CerasmartTM and Brilliant Crios, as well as the direct resin composite Grandio SO, were evaluated. Rectangular plates were cut from the blocks or fabricated using a silicon mold to obtain specimens for fracture toughness (KIc, n = 10), biaxial strength (σ0, n = 30) and cyclic fatigue testing (n = 30). Half of the specimens was stored for 24 h in dry conditions and the other half was aged for 60 days in distilled water at 37 °C. KIc was determined using the Compact-Tension (C(T)) method and σ0 and cyclic fatigue were tested using the Ball-on-Three-Balls assembly. Additional disc-shaped specimens (n = 5) were produced to obtain water sorption curves of the materials. Weibull statistics and two-way ANOVA with Tukey’s post-hoc test were used for data assessment. ResultsThe highest water sorption was observed for LavaTM Ultimate (42.6 μg/mm3), whereas Grandio SO displayed the lowest uptake (14 μg/mm3). A statistically significant drop in KIc and σ0 was measured for all materials after water storage, except for the σ0 of CerasmartTM. Water ageing had a dissimilar effect on the cyclic fatigue behavior, increasing the slow crack growth susceptibility of LavaTM Ultimate, but decreasing it for CerasmartTM and Brilliant Crios. SignificanceContemporary CAD/CAM resin composites are susceptible to water driven degradative processes, although differences in filler content and resin matrix constitution play an important role in how it impacts their mechanical properties.