Erosion analysis and reduction of curved-tee in pneumatic conveying system

Erosion and runoff reduction potential of vetiver grass for hill slopes: A physical model study

This paper shows the results of the monitoring carried out in three hilly farms of the MONACO project in order to verify the effectiveness of the Standard 1.1 (commitment a) (temporary ditches) and Standard 1.2 (commitment g) (Vegetation cover throughout the year in set-aside land) in the reduction in soil erosion, contained in Rule 1: ‘minimum land management that meets specific conditions’ of the decree Mipaaf 2009 and following modifications, until the recent decree No. 180 of January 23, 2015. In addition, the assessment of the competitiveness gap was done. That is the evaluation of the additional costs borne by the beneficiary of the single payment determined from agronomic commitments. Monitoring has also compared the erosion actually observed in the field with that predicted by RUSLE model (Revised Universal Soil Loss Equation) (Renard et al., 1997) in the two situations: with and without the presence of temporary ditches, i.e. assuming Factual (compliance rules) and in that Counterfactual (infringement). This comparison was made in view of the fact that the RUSLE model was chosen by the 'European Evaluation Network for Rural Development (EEN, 2013) as a forecasting tool for the quantification of' Common Indicator ‘soil erosion by water’. The results of soil erosion survey carried out by using a new UAV-GIS methodology on two monitoring farms in two years of observations have shown that temporary ditches were effective in decreasing erosion, on average, by 42.5%, from 36. 59 t ha-1 to 21.05 t ha-1 during the monitoring period. It was also evaluated the effectiveness of grass strips (at variance with the commitment of temporary ditches). The results showed a strong, highly significant, reduction in erosion by about 35% times respect soil erosion observed in bare soil and also a significant reduction in the volume of runoff water.  With regard to Standard 1.2 (commitment g) the statistical analysis shows a strong and highly significant decrease in the erosion due to the vegetation cover of the soil compared to bare soil. The economic competitiveness gap of Standard 1.1(commitment a) stood at € 4.07±1.42 € ha-1 year-1, while CO2 emissions due to execution of temporary ditches was 2.58 kg ha-1year-1. As for the Standard 1.2 (commitment g) the average differential competitiveness gap amounted to 50.22±13.7 € ha-1 year-1 and an output of CO2 equal to 31.52 kg ha-1 year.

Reduction of erosion by blistering in molybdenum surfaces with a multi-groove microstructure

Erosion studies were performed on a 30-cm diameter J-series ion engine modified for operation on xenon propellant. The erosion rates of molybdenum and tantalum badges placed at different locations within the discharge chamber were measured as a function of the percentage of nitrogen (by mass) added to the xenon propellant. Reductions in the erosion rates of these badges of a factor of 8 to 50 were observed at nitrogen addition fractions between 0.5 to 2.0 percent. Reductions in cathode-side baffle erosion were achieved by adding nitrogen to the xenon propellant or by increasing the cathode orifice diameter. Analyses show that no significant degradation in ion engine performance should be expected at these nitrogen mass fractions. XRD, XPS and Auger analyses indicate the existence of nitrogen and nitrides in the surface of some but not all of the badges used in the tests where nitrogen was added to the xenon. Difficulty in identifying surface nitrides in the samples may be due to the existence of surface oxides and contaminants, or to the small thicknesses of the nitride layers.

A cost analysis approach to valuing cover crop environmental and nitrogen cycling benefits: A central Illinois on farm case study

Erosion measurements were performed on a modified J-series 30 cm ion engine operating on xenon propellant. The data indicate that a factor of 15 reduction in erosion of the upstream baffle face can be obtained by introducing nitrogen into the xenon propellant. Minor design changes to reduce spalling coupled with the reduction in baffle erosion may increase the operating life of xenon ion engines.

Coastal hazards, such as erosion and flooding, pose significant threats to many coastal areas, and in extreme cases, have led to the decimation of some coastal communities. Historically, management has mostly focused on the use of grey infrastructure such as seawalls and groynes. However, these interventions are costly and can cause unintended consequences, promoting a shift toward Nature-based Solutions (NbS), such as the use of mangroves. Mangroves, particularly, have been proven to protect shorelines due to their ability to attenuate waves and trap sediment. However, there is limited research, particularly in data-deficient regions such as Ghana, West Africa, to support such NbS initiatives. This study explored the potential of mangroves as NbS to mitigate coastal erosion, using the 1D morphodynamic model XBeach. The baseline model was validated against measured coastal profiles, and the results show accurate predictions of sediment volume changes with an overall RMSE of 0.75 m. Based on the calibrations, we explored the effects of mature mangroves at varying densities on the berm and within the intertidal zone under current and projected sea level conditions, on coastal erosion. The results show a significant reduction in sediment volume erosion from 28 m3 to 0.9 m3 in the current situation, representing 97% protection; and from 468 m3 to 2.6 m3 under future sea level rise of 0.233 m by 2040, indicating 99% protection. Notably, high densities of mangroves, introduced on the berm, which is more practical for the area, provided up to 53% reduction in erosion for the current situation and 97% for the future. These scenario-based simulations demonstrate the potential of mangroves as a dynamic coastal defense strategy, with the approach providing a valuable tool for testing and optimizing NbS interventions.

There is an increasing need for improved process-based decision support tools for watershed management. Many of the tools available to assist managers in locating and selecting effective management practices are either too general or too complex to be used practically. Empirical models based on historic data may not be relevant to future climates. In this study, we present a simple web-based Hydrologic Characterization Tool (HCT) that can be used to analyze the effects of management practices on the hydrology, erosion, and sediment delivery within specific landscapes. The HCT, based fundamentally on the Water Erosion Prediction Project model, was developed as a simple tool to help managers build a process-based understanding of the hydrologic flow paths and the processes driving erosion for common management practices within a region. Users select a range of soil characteristics, slope attributes, and crop rotations common for their region and then select management options which are currently being applied in the region or are being considered as potential future conservation options. The HCT then creates input files for all possible combinations of attributes and provides annual and monthly hydrologic and soil erosion output for both within and at the outlet of each hillslope. The output allows users to not only compare the effect of the management practices for a single attribute, for example a reduction in soil erosion, but it provides them with an understanding of the effect of the practices on the hydrologic flow paths generating and delivering the pollutant through the hillslope. We illustrate characterizations from two regions of the US: Idaho and Iowa. Each of these locations has a unique set of climatic, topographic, and soil characteristics resulting in much different dominant hydrologic flow paths. We demonstrate that adoption of conservation/mulch tillage practices in Idaho effectively converts the dominant runoff generating process from an infiltration excess to saturation excess mechanism leading to a reduction in erosion. Understanding the interaction between soil depth and topography is critical for identifying saturation-excess processes. In contrast, since the rainfall intensities in Iowa are much greater than in Idaho, conservation tillage practices alone are not as effective at reducing erosion in Iowa as in Idaho. Managers in Iowa often must use terracing practices along with conservation tillage to successfully reduce erosion rates to acceptable levels. In addition to sediment transport we demonstrate how the HCT can be used to identify sensitive areas for soluble pollutants. Future versions of the tool will provide direct prediction of transport of nitrate, phosphorus, and pesticides within each landscape.

A two year randomised controlled trial of intramuscular depot steroids in patients with established rheumatoid arthritis who have shown an incomplete response to disease modifying antirheumatic drugs

The paper aims to report the comparative of erosion on conventional vis a vis textured carbon steel surfaces wherein alumina particles have been used as erodent. Shaping and stamping processes were employed to prepare textured surfaces on carbon steel that comprised of trapezoidal and rasp shapes. Experiments were performed employing alumina particles as erodent striking the carbon steel plates at the impact angles of 15°, 30° and 45°. With due consideration to the particle aspect during exploration, the erodent was made to strike the surface with two impact velocities of 30m s−1 and 60 m s−1. With the aforesaid parameters and surface condition, experiment was performed for both unhardened and hardened surfaces (total 36 test specimen were used). Textured carbon steel (comprising trapezoidal shape) yielded significant reductions (40%–50%) in erosion in comparison to the conventional case. The reduction in erosion for rasp shape specimen was in a range of 15%–17%. It is worth noting here that the presence of texture has immensely contributed in erosion reduction of unhardened samples as compared to the hardened conventional samples.

In which cropping systems can residual weeds reduce nitrate leaching and soil erosion?

Effects of air bubble quantity on the reduction of cavitation erosion

To address the issues of severe local erosion and uneven service life of flow components in mining metal slurry pumps, this article aims to utilize biomimetic methods to design the biomimetic schemes, reveal the biomimetic erosion reduction mechanism, and achieve erosion reduction and balance. First, a solid–liquid two-phase flow numerical calculation model is established based on the irregular particle collision model. Hydraulic performance and erosion law experiments are conducted to verify the model's accuracy, and the erosion laws of the traditional mining metal slurry pump are revealed. Subsequently, different biomimetic configurations, directions, and combinations are carried out for the impeller and sheath's design based on the shell surface morphology. Then, the erosion distribution and amount of the impeller and sheath, the particle motion behaviors, and the flow field flow characteristics are explored under different biomimetic schemes. Finally, the biomimetic scheme with optimal erosion reduction and balance is obtained, and the erosion reduction mechanism of different biomimetic designs is revealed. The experimental results show that when using the groove biomimetic configuration, perpendicular direction, and impeller+sheath combination scheme, the mining metal slurry pump has relatively optimal erosion reduction and balance. Compared to the non-biomimetic design scheme, the total erosion decreases by 24.0%, and the difference in erosion between the impeller and sheath decreases by 77.4%. This study presents a new technological path and entry point for reducing erosion and extending the service life of mining metal slurry pumps and other turbine machinery.

Rainfall-induced wind erosion in soils stabilized with alkali-activated waste materials

The objective of this project was the reduction of erosion in elbows (bends), in pneumatic transport systems, due to flow field modification. Air was to be injected into a bend, thus modifying the flow so that the eroding particles are kept from the surfaces. The goal of this effort was to achieve erosion rates less than those of blind-tees. A fluidized blind-tee and two different air injection bends were selected for detailed investigation. The detailed investigation demonstrated that the air injection bends significantly reduced erosion rates, but never developed an erosion rate less than that for a blind-tee. Although the air injection bends' erosion rates approached those for a blind-tee; technically the blind-tee represents a simpler system and consequently will probably remain the choice of engineers concerned with erosion of bends. 20 figs., 8 tabs.