Estimation of anti-erosion effect of narrow forest belts around illuvial meadows

Novosilskaya zonal agroforestry experimental station was founded in 1921 for development measures to combat water erosion. In the article, the authors carried out the research to identify the soil-protective efficiency of agroforestry-meadow reclamation measures of the anti-erosion complex. The creation of spruce strips around the meadows, on the slope lands of the Glubkovsky dry fields contributed to a radical change in the soil cover: an increase in the humus horizon, the content of humus, and a decrease in the bulk mass. The studied anti-erosion measures had a positive effect on the fertility of illuvial soils.

Dental Erosion: Effect of Diet Drink Consumption on Permanent Dentition

Objective: The aim of this study is to examine the effect of diet drinks on dental erosion among a representative sample of US adults. Methods: Adult dietary and dental data were analyzed from the 2003–2004 cycle of the National Health and Nutrition Examination Survey. Erosion was measured with a modified tooth wear index and was analyzed as a dichotomous variable. Cluster analysis was performed, and the cluster number was based on having a separate diet drink cluster and the R2 values. Survey procedure and sample weights were used. Results: Most of the population (80%) had some form of dental erosive lesions. When compared with the total sample, people with erosion were more likely to be male (52.5%) and older. People with no erosive lesions were younger (42.3%) and non-Hispanic Black (21.2%). Cluster analysis resulted in 4 distinct clusters: high water, high diet drinks, high coffee/tea, and high soda. The respective percentage of individuals in each cluster who had erosion was 78.9%, 85%, 83.9%, and 76.2%, where the “high diet drinks” cluster showed the highest erosion ( P = 0.28). Logistic regression modeling showed that the “high diet drinks” cluster had increased odds of erosion (odds ratio = 1.27; 95% CI = 0.58 to 2.77) when compared with the “high water” cluster, but the relationship was not statistically significant. Conclusion: High diet drinks consumption slightly increased the odds of dental erosion among US adults, although this relationship was not statistically significant. It is thus not yet clear that dentists should recommend diet drinks, as they might be linked to systemic diseases. Further research is needed to explore more about risk factors of erosion. Knowledge Transfer Statement: The findings of this study are suggestive, though not significantly, that diet drinks may increase risk for dental erosion. While further research is needed, it is not clear that dentists should recommend these drinks as healthy substitutes for sugary drinks.

Erosive Degradation Study of Concrete Augmented by Mussel Shells for Marine Construction

This work proposes a green material for artificial reefs to be placed in Galicia (northwest Spain) taking into account the principles of circular economy and sustainability of the ecosystem. New concrete formulations for marine applications, based on cement and/or sand replacement by mussel shells, are analyzed in terms of resistance to abrasion. The interest lies in the importance of the canning industry of Galicia, which generates important quantities of shell residues with negative environmental consequences. Currently, the tests to determine the abrasion erosion resistance of concrete on hydraulic structures involve large and complex devices. According to this, an experimental test has been proposed to estimate and compare the wear resistance of these concretes and, consequently, to analyze the environmental performance of these structures. First, a numerical analysis validated with experimental data was conducted to design the test. Subsequently, experimental tests were performed using a slurry tank in which samples with conventional cement and sand were partially replaced by mussel shell. The abrasive erosion effect of concrete components was analyzed by monitoring the mass loss. It shows an asymptotic trend with respect to time that has been modeled by Generalized Additive Model (GAM) and nonlinear regression models. The results were compared to concrete containing only conventional cement and sand. Replacing sand and/or cement by different proportions of mussel shells has not significantly reduced the resistance of concrete against erosive degradation, except for the case where a high amount of sand (20 wt.%) is replaced. Its resistance against the erosive abrasion is increased, losing between 0.1072 and 0.0310 wt.% lower than common concrete. In all the remaining cases (replacements of the 5–10 wt.% of sand and cement), the effect of mussel replacement on erosive degradation is not significant. These results encourage the use of mussel shells in the composition of concrete, taking into account that we obtain the same degradation properties, even more so considering an important residue in the canning industry (and part of the seabed) that can be valorized.

DAMAGE CHARACTERISTICS OF RECYCLED ASPHALT MIXTURES UNDER THE EROSION EFFECT OF SNOW-MELTING SALT

The erosion effect of snow-melting salt will degrade the durability of recycled asphalt pavement, but the damage characteristics of recycled asphalt mixture triggered by the erosion effect of snow-melting salt remain unclear. To solve the snow-melting salt-induced durability degradation of asphalt pavement, two commonly used snow-melting salts, NaCl and CaCl2, were selected to carry out the saline water immersion, salt-drying and -wetting cyclic and salt-freezing and -thawing cyclic splitting tests on recycled asphalt mixture, and the attenuation laws of splitting strengths and its damage characteristics under the erosion effect of snow-melting salts were analyzed. Results demonstrate that with the increase in soaking time, salt-drying and -wetting cycles and salt-freezing and -thawing cycles, the splitting strength of the recycled asphalt mixture maintain a declining trend, and the attenuation rate of splitting strength is elevated. The damage degree of the recycled asphalt mixture presents a nonlinear growth trend during saline water immersion, salt-drying and -wetting cycles, and salt-freezing and -thawing cycles. Under the same conditions, the damage degree after the action of NaCl solution is higher than that after the action of CaCl2 solution, and meanwhile, within the range of test concentration, the damage degree after the action of low-concentration saline solution is higher than that after the action of high-concentration saline solution. Conclusions provide a significant reference for the composition design and maintenance decisions of recycled asphalt pavement materials in cold regions. Keywords: road engineering; salt erosion; recycled asphalt mixture; damage characteristics; splitting strength

CFD Analysis on Francis Turbine to Analyse Erosion Wear Due to Sediment Flow

In present work Computational fluid dynamics analysis based erosion wear prediction is performed for Francis turbine components, especially the runner. For the geometrical parameters, Francis turbine model with steady state condition and viscous flow turbulence SST model using ANSYS Fluent. The erosion effect on all the three component such as spiral casing, runner & draft tube has been studied for different concentration of sand particles from 1% - 6%. For each of those concentration the effect of variation in size has been studied for different sizes 10 ?m - 80 ?m. Further the effect of total erosion was also analyzed for different particle size. Erosion damage is found close to the upper and lower portions of the leading edge of the stay vane. some erosion spots at guide vane on the blade pressure side where suction side has minimum erosion. Maximum erosion damage observed on runner especially at the middle of the blade. The draft tube situated closer to runner having highest velocity due to high absolute velocity of water coming out from the runner does not produce any serious erosion effect. Results shows that erosion rate is maximum on runner at particle size 80 ?m for all sand concentration 1% to 6% and minimum at 30 ?m. Thus, 30 ?m is the optimum size of sand particles for the erosion.

A Review on the Erosion Mechanism in Cavitating Jets and Their Industrial Applications

Cavitating jets have been widely studied for over a century, but despite the extensive literature on this subject, the implementation of cavitating jets in many industries is still very limited due to technical challenges. The main purpose of the present paper is to provide recommendations on using the cavitating jets based on a comprehensive literature review on the erosion mechanism in these jets. Self-resonating jets are extensively discussed in the present paper due to their importance in amplifying the erosion effect of cavitating jets. The influence of different jet nozzle geometric parameters and the operating conditions of the cavitating jet flow on the erosion mechanism is also discussed. Finally, well drilling in addition to multiple other industrial applications of cavitating jets are examined.

Lenience breeds strictness: The generosity-erosion effect in hiring decisions

In recruitment processes, candidates are often judged one after another. This sequential procedure affects the outcome of the process. Here, we introduce the generosity-erosion effect, which states that evaluators might be harsher in their assessment of candidates after grading previous candidates generously. Generosity is defined as giving a candidate the lowest possible grade required to progress in the hiring process. Analyzing a high-stake hiring process, we find that for each candidate graded generously, the probability for subsequent candidates to pass decreased by 7.7% (experiment 1; N = 11,281). Testing the boundary conditions of the generosity-effect, we explore a hiring process that, in contrast to the previous process, was very selective, because candidates were more likely to fail than to pass. In this scenario, no evidence is found for the generosity-erosion effect (experiment 2; N = 3171). Practical implications and mechanisms underlying the generosity-erosion effect are further discussed.