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Most commercially-available mechanical testing devices are bulky, expensive, and unable to evaluate changes in sample microstructure under load. This leaves a crucial gap in understanding between material structure and bulk mechanical properties. Our objective was to fabricate a mechanical testing device small enough to fit in most upright or inverted microscopy stages and able to position samples to allow for simultaneous mechanical and microstructural characterization. Parts were 3D printed using the hobbyist-friendly Fused Filament Fabrication technique, then assembled with commercial fasteners and translation components to create a mechanical testing device that utilized the deflection of plastic posts to determine sample reaction forces under applied strain. Video of sample deformation was analyzed using a custom processing script to calculate stress and strain behavior in an automated and high-throughput manner. This device was able to perform mechanical characterization with an accuracy comparable to commercial mechanical testing devices for a wide range of nonlinear and viscoelastic samples under dry and hydrated conditions. Additionally, the device showed compatibility with different upright and inverted microscopes and was able to demonstrate accurate mechanical testing results when used with these instruments. We successfully developed a device capable of accurately testing a majority of soft materials in the field of Biomedical Engineering with the ability to perform additional microstructural characterization using microscopy at a price point of $600. [ABSTRACT FROM AUTHOR]

The sediment flux through Himalayan rivers directly impacts water quality and is important for sustaining agriculture as well as maintaining drinking-water and hydropower generation. Despite the recent increase in demand for these resources, little is known about the triggers and sources of extreme sediment flux events, which lower water quality and account for extensive hydropower reservoir filling and turbine abrasion. Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001-2009) from four sites along the Sutlej River and from four of its main tributaries. In conjunction with satellite data depicting rainfall and snow cover, air temperature and earthquake records, and field observations, we infer climatic and geologic controls of peak suspended sediment concentration (SSC) events. Our study identifies three key findings: First, peak SSC events (≥99th SSC percentile) coincide frequently (57-80 %) with heavy rainstorms and account for about 30% of the suspended sediment flux in the semi-arid to arid interior of the orogen. Second, we observe an increase of suspended sediment flux from the Tibetan Plateau to the Himalayan Front at mean annual timescales. This sediment-flux gradient suggests that averaged, modern erosion in the western Himalaya is most pronounced at frontal regions, which are characterized by high monsoonal rainfall and thick soil cover. Third, in seven of eight catchments, we find an anticlockwise hysteresis loop of annual sediment flux variations with respect to river discharge, which appears to be related to enhanced glacial sediment evacuation during late summer. Our analysis emphasizes the importance of unconsolidated sediments in the high-elevation sector that can easily be mobilized by hydrometeorological events and higher glacialmeltwater contributions. In future climate change scenarios, including continuous glacial retreat and more frequent monsoonal rainstorms across the Himalaya, we expect an increase in peak SSC events, which will decrease the water quality and impact hydropower generation. [ABSTRACT FROM AUTHOR]

Soil erosion and sediment yield are strongly affected by land use/land cover (LULC). Spatially distributed erosion models are of great interest to assess the expected effect of LULC changes on soil erosion and sediment yield. However, they can only be applied if spatially distributed data is available for their calibration. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small (2.84 km²) experimental catchment in the Central Spanish Pyrenees. Model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space, which was not possible to attain if only external (not spatially distributed) sediment yield data were available. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios were then modeled to reproduce land use at the beginning of the twentieth century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350Mgyr-1) and sediment delivery (11.2 to 1.2Mgyr-1 ha-1) during the last decades as a result of the abandonment of traditional land uses (mostly agriculture) and subsequent vegetation recolonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment. [ABSTRACT FROM AUTHOR]

A landslide affecting two small villages located on the Northwestern Italian Apennines has been investigated since the year 2000 through the use of different equipment. A complex monitoring system has been installed in the area. The system includes several inclinometers, piezometers and a raingauge. An Automatic Inclinometric System (AIS) has been also installed that automatically performs measurements, twice a day, along the entire length of a pipe that is 45m deep. This monitoring system has been set up to identify a methodology that allowed to deal with landslides, trying to predict their behaviour beforehand for warning purposes. Previous researches carried out in the same area for a period of about 7 months, in the year 2000, have allowed to identify a correlation between deep slope movements and rainfalls. In particular, it has been possible to determine the time lag needed for a rainfall peak to produce a corresponding peak of the landslide movements; this time lag was of 9 days. This result was possible because the AIS allows to obtain, as mentioned, daily inclinometric measurements that can be correlated with the recorded rainfalls. In the present report we have extended the analysis of the correlation between deep slope movements and rainfalls to a greater period of observation (2 years) to verify over this period the consistency of the time lag mentioned above. The time lag previously found has been confirmed. We have also examined the possibility to extend to the entire landslide body the correlation that has been found locally, analyzing the results of the remaining inclinometric tubes with traditional reading installed on the landslide and comparing them with the results of the AIS. The output of the tubes equipped with piezometric cells has also been analyzed. The relations existing among rainfalls, ground water level oscillations and the related slope movements have been explored. [ABSTRACT FROM AUTHOR]