Environmental Consequences of Soil Erosion

Soil is one of the most valuable natural resources. Despite soil importance, the pressures on soil have increased in recent decades. Soil degradation is a critical and growing problem, whereby soil erosion presents a prevailing process compared to other degradative processes. The intensity of erosion depends on the topography, climate conditions, soil characteristics, human activities, and the presence of vegetation. In this chapter, the diverse factors that cause soil erosion have been evaluated. The level of damage associated with soil erosion has been analyzed, with emphasis on the impacts they may have on the global carbon cycle, phosphorus loss, dust emissions, eutrophication, and soil biodiversity.

Predictive Analytical Modeling of Thermo-Mechanical Effects in Orthogonal Machining

Factor relationships in a machining system do not work in pairs. Varying the cutting parameters, materials machined, or volumes produced will influence many machining characteristics. For this reason, we are attempting to better understand the effect of the Johnson-Cook (J-C) law of behavior on cutting temperature prediction. Thus, the objective of the present study is to investigate, experimentally and theoretically, the tool/material interactions and their effects on dust emission during orthogonal cutting. The proposed approach is built on three steps. First, we established an experimental design to analyze, experimentally, the cutting conditions effects on the cutting temperature under dry condition. The empirical model which is based on the response surface methodology was used to generate a large amount of data depending on the machining conditions. Through this step, we were able to analyze the sensitivity of the cutting temperature to different cutting parameters. It was found that cutting speed, tool tip radius, rake angle, and the interaction between the cutting speed and the rake angle explain more than 84.66% of the cutting temperature variation. The cutting temperature will be considered as a reference to validate the analytical model. Hence, a temperature prediction model is important as a second step. The modeling of orthogonal machining using the J-C plasticity model showed a good correlation between the predicted cutting temperature and that obtained by the proposed empirical model. The calculated deviations for the different cutting conditions tested are relatively acceptable (with a less than 10% error). Finally, the established analytical model was then applied to the machining processes in order to optimize the cutting parameters and, at the same time, minimize the generated dust. The evaluation of the dust generation revealed that the dust emission is closely related to the variation of the cutting temperature. We also noticed that the dust generation can indicate different phenomena of fine and ultrafine particles generation during the cutting process, related to the heat source or temperature during orthogonal machining. Finally, the effective strategy to limit dust emissions at the source is to avoid the critical temperature zone. For this purpose, the two-sided values can be seen as combinations to limit dust emissions at the source.

Investigation of air pollution with fine dust during repair and construction work inside premises

A study of the dispersed composition of dust for various types of repair in warehouses has been carried out. The data on the concentration of dust emissions inside the premises were obtained. The dependence of the dust concentration on the distance from the place of work, the size of the emitted particles, the area of the room and the time spent on the work is built. An assessment is given of the impact of reconstruction work in warehouses on environmental pollution by dust emissions. The concentration and ratio of PM2.5 to PM10 particles were calculated to determine dustiness and negative impact on the environment.

Contemporary and future dust sources and emission fluxes from gypsum- and quartz-dominated eolian systems, New Mexico and Texas, USA

Recent research on dust emissions from eolian dunes seeks to improve regional and global emissions estimates and knowledge of dust sources, particularly with a changing climate. Dust emissions from dune fields can be more accurately estimated when considering the whole eolian system composed of active to stabilized dunes, interdunes, sand sheets, and playas. Each landform can emit different concentrations of dust depending on the supply of silt and clay, soil surface characteristics, and the degree to which the landforms are dynamic and interact. We used the Portable In Situ Wind Erosion Laboratory (PI-SWERL) to measure PM10 (particulate matter <10 μm) dust emission potential from landforms in two end-member eolian systems: the White Sands dune field in New Mexico (USA), composed of gypsum, and the Monahans dune field in west Texas, composed of quartz. White Sands is a hotspot of dust emissions where dunes and the adjacent playa yield high dust fluxes up to 8.3 mg/m2/s. In contrast, the active Monahans dunes contain 100% sand and produce low dust fluxes up to 0.5 mg/m2/s, whereas adjacent stabilized sand sheets and dunes that contain silt and clay could produce up to 17.7 mg/m2/s if reactivated by climate change or anthropogenic disturbance. These findings have implications for present and future dust emission potential of eolian systems from the Great Plains to the southwestern United States, with unrealized emissions of >300 t/km2/yr.

Development and testing of a tool for the decontamination of corners and inner edges on concrete surfaces

For the decontamination of flat concrete surfaces, a wide variety of tools are available; however, these tools cannot be used for the decontamination of corners, inner edges, gaps and other geometrical discontinuities. Currently, these areas are worked by hand-held tools with a connected vacuum exhaust system to reduce dust emissions. The combination of using heavy hand-operated tools with exhaust systems on difficult to access areas as well as the forces and vibration of the tools, make the task of decontamination a burden and add additional physical stress for the operator. The goal of the research project called EKont, funded by the German Ministry for Education and Research, BMBF), is, to develop an innovative semi-automated demonstrator for dry mechanical decontamination of corners, edges and geometrical discontinuities in nuclear facilities. The tool will have a flexible housing with an integrated exhaust system to reduce the dust load. This specialized tool should make the decontamination of corners and inner edges more effective regarding time and the generation of secondary waste and should further spare the musculoskeletal system of the operator physical stress by lowering the vibrations and weight of the tool. For this task, a test bench for testing and evaluating different methods of surface decontamination has been set up. The test bench enables the measurement of forces and vibrations of the machine during the decontamination and the dust emissions. Based on the analysis of different decontamination methods and tools, four prototypes are being developed. This project also aims at the scientific investigation of experimentally collected performance parameters, such as feed rate, removal depth per operation, surface roughness and removal rate, in order to determine the relevant parameters of the developed prototypes. A field test of the prototypes together with decommissioning companies is scheduled. The prototype is not limited to use in nuclear facilities but later can also be used in conventional fields, for example in the decontamination of materials containing PCBs and asbestos. In this presentation the EKont test bench and prototypes will be explained and the test results will be presented.