FG-LiquID

Contact-less liquid identification via wireless sensing has diverse potential applications in our daily life, such as identifying alcohol content in liquids, distinguishing spoiled and fresh milk, and even detecting water contamination. Recent works have verified the feasibility of utilizing mmWave radar to perform coarse-grained material identification, e.g., discriminating liquid and carpet. However, they do not fully exploit the sensing limits of mmWave in terms of fine-grained material classification. In this paper, we propose FG-LiquID, an accurate and robust system for fine-grained liquid identification. To achieve the desired fine granularity, FG-LiquID first focuses on the small but informative region of the mmWave spectrum, so as to extract the most discriminative features of liquids. Then we design a novel neural network, which uncovers and leverages the hidden signal patterns across multiple antennas on mmWave sensors. In this way, FG-LiquID learns to calibrate signals and finally eliminate the adverse effect of location interference caused by minor displacement/rotation of the liquid container, which ensures robust identification towards daily usage scenarios. Extensive experimental results using a custom-build prototype demonstrate that FG-LiquID can accurately distinguish 30 different liquids with an average accuracy of 97%, under 5 different scenarios. More importantly, it can discriminate quite similar liquids, such as liquors with the difference of only 1% alcohol concentration by volume.

Mechanical Modeling of Frozen Coarse-Grained Materials Incorporating Microscale Investigation

In the cold regions of China, coarse-grained materials are frequently encountered or used as backfilling materials in infrastructure construction, such as dams, highways, railways, and mineral engineering structures. Effects of confining pressure (0.2, 0.5, and 1 MPa) and frozen temperature (−2, −5, −10, and −15°C) on the stress-strain response and elastic modulus were investigated using triaxial compression tests. Moreover, the microscale structures of a coarse-grained material were obtained by X-ray computed tomography. The coarse-grained material specimens exhibited strain-softening and significant dilatancy behaviors during shearing. A modified model considering microstructures of the material was proposed to describe these phenomena. The predicted values coincided well with the experimental results obtained in this study and other literatures. The sensitivity analysis of parameters indicated that the model can simulate the initial hardening and post-peak strain-softening behavior of soils. And the transition of volume strain from contraction to dilatancy can also be described using this model. The results obtained in this study can provide a helpful reference for the analysis of frozen coarse-grained materials in geotechnical engineering.

COARSE ICE SPREAD MATERIAL ON THE BOTTOM OF THE BARENTS SEA

The coarse-grained material (CGM) obtained at 89 stations in 67 and 68 cruises of the R/V “Akademik Mstislav Keldysh” when washing modern sediments was studied. Its petrographic composition was studied, 35 petrographic types and subtypes of rocks were identified, their cyclograms were compiled. It was noted that the CGMof the Barents Sea is subject to significant fluctuations, but in general, it is complementary to the set of rocks of the adjacent land and is quantitatively ensured by the size of the examination and the removal of the material by the glacier to the sedimentation areas. Such mobility of the CGM makes it difficult to use it as a marker for geo-mapping the bottom of the Barents Sea.

Double-Exposure Method with Synchrotron White X-ray for Stress Evaluation of Coarse-Grain Materials

Stress measurements of coarse-grained material are difficult using synchrotron X-ray diffraction because the diffraction patterns of coarse-grained materials are spotty. In addition, the center of the diffraction pattern is unknown for the transmitted X-ray beam. Here, a double-exposure method is proposed as the countermeasure against this issue. In the experiment, we introduce a CdTe pixel detector. The detector is a newly developed area detector and can resolve high-energy X-rays. The strains of the coarse-grained material can be measured using a combination of the double-exposure method, white synchrotron X-ray, and the CdTe pixel detector. The bending stress in an austenitic stainless steel plate was measured using the proposed technique. As a result, the measured stress corresponded to the applied bending stress.

Micro Parameters Sensitivity of Coarse Grained Material in Mechanics and Deformation Based on PFC3D

In order to study the effects of various parameters on macro-mechanical and deformational characteristics of coarse grained material based on discrete element method, triaxial tests have been conducted. Weighted average assembling method is used to assemble the numerical model based on PFC3D. The ratio of normal and shear stiffness of particles (kn/ks), shearing rate and friction coefficient are chosen as micro parameters to analyze the influential sensitivity. Curves of stress-strain intensity are taken as the mechanical analytic method. The particle rotation field as deformation analysis method is proposed to sort the sensitivity of these parameters in strength and deformation of coarse grained material. The research shows that the parameters have a certain effect on the strength and deformation of coarse grained material. kn/ks has the greatest influence on both. The sensitive list of the strength and deformation hopefully can be discussed with the relevant scholars, which can provide a reference for the adjustment of micro parameters in numerical field.