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A fiber-optic gyroscope (FOG) with lower precision but higher cost advantage is typically selected according to working conditions and engineering budget. Thermal drift is the main factor affecting FOG precision. External thermal calibration methods by algorithms can effectively weaken the influence of thermal drift. This paper presents a thermal calibration method of a two-dimensional N-order polynomial (TDNP) and compares it with artificial neural network (ANN) methods to determine a software FOG thermal calibration method for landslide displacement monitoring. The TDNP thermal calibration coefficient matrix was established, and the thermal calibration capability of the TDNP method with different orders N was evaluated on the basis of error analysis. The ANN model with 1 to 18 hidden neural layers was established on the basis of LM, BR, and SCG algorithms to choose a suitable ANN. Finally, the mean absolute errors of FOG thermal calibration through the TDNP with different orders and the LM were compared. This method was applied in the Huangtupo landslide area, China. The results highlight that the TDNP method with order 5 had better performance and satisfied the requirements of landslide displacement monitoring. The research results can compensate for the lack of adaptability of the FOG thermal calibration method in landslide displacement monitoring. [ABSTRACT FROM AUTHOR]

Classifying big data in hyperspectral imaging (HSI) can be challenging when minor (low-concentrated) compounds are present in actual samples, as for chemical additives and adulterants in food matrix. Herein, we propose a new strategy to classify HSI data for the identification of adulterants in food material for the first time. This strategy is based on the selection of essential spectral pixels of full HSI data followed by the feature space construction using uniform manifold approximation and projection as well as the data clustering utilizing hierarchical clustering analysis on the reduced data (named ESPs-UMAP-HCA). We apply our approach to analyze two real NIR datasets and four new Raman datasets. Compared with non-ESPs UMAP-HCA and t-distributed stochastic neighbor embedding combined with ESPs and HCA (ESPs-t-SNE-HCA), the developed strategy provides well-separated clusters for major and minor compounds in food matrix. Finally, the adulterants as minor compounds are accurately identified, which is confirmed by the fact that the extracted spectra of them perfectly match with their pure spectra. In addition, their locations are found in the contribution map even though they are present in a few pixels. What's more, the proposed strategy does not need any a priori knowledge of the data structure and the class memberships and therefore reduced the studied difficulty and confirmation bias in the analysis of big HSI datasets. Overall, the proposed ESPs-UMAP-HCA method could be a potential approach for food adulteration detection. [Display omitted] • ESPs-UMAP-HCA was developed for the classification of hyperspectral imaging data. • The proposed method was validated for both NIR and Raman HSI datasets. • Compared with non-ESPs UMAP-HCA and ESPs-t-SNE-HCA, the approach provided well-separated clusters. • The developed method was applied to identify adulterants in food matrix. [ABSTRACT FROM AUTHOR]

Incidents such as borehole collapse, suction drill, and drill pipe drop resulting from borehole instability may occur in the process of drilling in loose coal bed sections for coal mine methane (CMM) drainage before mining. Grouting while drilling (GWD) is a technique used to reduce such incidents. Sodium Silicate used in GWD has the advantages of controllable consolidation-time, non-toxic material, non-pungent odor and relatively inexpensive. Although it will shrink after solidification, this could be used to connect gas channels. This paper presents the feasibility of using Sodium Silicate to make GWD slurry through results of laboratory experiments. The principal ingredients of the two Sodium Silicate grouting slurry formulae, namely 4% Glycerol Triacetate with 20–40% Sodium Silicate and 4% 1,4-Butyrolactone with 20–40% Sodium Silicate, were selected based on the requirements of GWD. The experimental results from a traditional test device revealed that coal cement stress is still low after 45 min thus limiting its field application. However, after 72 h, multiple cracks appear along the edge of the coal grains suggesting that the formulae can be used to connect gas channels naturally after hardening. If a PH stabilizer is not added, the optimal grouting time occurs within 20 min. In the process of GWD, the grouting slurry will not consolidate until it is injected into the borehole wall, which is enables the drill pipe to remain clean after grouting. Seepage grouting simulation experiments based on a self-developed device indicate that injecting certain slurry into pre-set positions of a drilling hole by circulation wind pressure is feasible to some extent when drilling in fractured, strongly fractured, and pulverized coal beds. In powder coal, however, it will close the gas channels, and thus cannot be applied. [ABSTRACT FROM AUTHOR]

The global annual consumption of marine metal corrosion is a significant challenge to the service life of metals and the development of marine strategies. A tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush (NB) superstructure photoanode is constructed. It shows superior photoelectric cathodic protection (PECP) characteristic for pure copper whose self-corrosion potential is more negative in simulated natural marine environment without additional any hole scavengers under simulated solar light illumination. Origin from the more negative energy level potential of AgInS2/In2S3, the quasi-Fermi level of the photogenerated electrons of TiO2 NB/AgInS2/In2S3 was pull to a more negative position, reinforcing the transmission of photogenerated electrons to the pure copper whose self-corrosion potential is more negative. The sensitizer AgInS2 together with the assistant layer In2S3 dramatically enhances the PECP performance of TiO2 NB/AgInS2/In2S3. The tri-dimensional ultrafine branch-like architecture of TiO2 NB with the nanoparticles quickens the collection and transfer of photogenerated electrons to the metallic pure copper. This environmentally friendly 3D photoanode structure provides a good reference for the optimized construction of photoelectric materials for marine metal corrosion protection. The tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush superstructure photoanode possesses superior photoelectric cathodic protection characteristic for pure cooper whose self-corrosion potential is more negative in simulated marine environment under simulated solar light illumination. [ABSTRACT FROM AUTHOR]

Landslide displacement monitoring plays a fundamental role in the study of landslide evolution mechanisms, forecasting, risk assessment, prevention, and control. To fill the deficiencies of traditional instrumentation for measuring landslide displacement distributed along lateral direction, a landslide displacement measurement method based on deformation-coupled pipeline trajectory measurement is proposed, and a pipeline trajectory inertial measurement instrument is developed. The developed instrument, primarily comprised of a single shaft gyro, two axis accelerometers, and an external roller encoder, is designed as an axial half strapdown-radial half platform structure combined with a mechanical gravity platform. This structure avoids the singularity of pitch angle and roll angle and can expediently calculate a pipeline trajectory with an Eulerian transformation when obtaining several basic physical variables, e.g., the axial linear velocity, pitch angle, roll angle, and azimuth angle. Additionally, the pipeline trajectory, measured at different times, possesses the ability to reflect the displacement evolution feature of landslides. The results of prototype simulation tests imply a single measurement accuracy of a 12 cm/100 m span and a singly periodic multiple (more than five times) measurement accuracy of a 3 cm/100 m span, which meets medium-precision displacement measurement requirements for a landslide. Additionally, the finished instrument has been successfully applied to the deformation monitoring of the Majiagou I# landslide, which further verifies its feasibility and offers a reference for similar landslides. [ABSTRACT FROM AUTHOR]

The physical model test of landslides is important for studying landslide structural damage, and parameter measurement is key in this process. To meet the measurement requirements for deep displacement in landslide physical models, an automatic flexible inclinometer probe with good coupling and large deformation capacity was designed. The flexible inclinometer probe consists of several gravity acceleration sensing units that are protected and positioned by silicon encapsulation, all the units are connected to a 485-comunication bus. By sensing the two-axis tilt angle, the direction and magnitude of the displacement for a measurement unit can be calculated, then the overall displacement is accumulated according to all units, integrated from bottom to top in turn. In the conversion from angle to displacement, two spline interpolation methods are introduced to correct and resample the data; one is to interpolate the displacement after conversion, and the other is to interpolate the angle before conversion; compared with the result read from checkered paper, the latter is proved to have a better effect, with an additional condition that the displacement curve move up half the length of the unit. The flexible inclinometer is verified with respect to its principle and arrangement by a laboratory physical model test, and the test results are highly consistent with the actual deformation of the landslide model. [ABSTRACT FROM AUTHOR]

• ZnIn 2 S 4 /TiO 2 nanoflowerbush photoanode was prepared by facile hydrothermal method. • The nanoflower-like ZnIn 2 S 4 was tightly incorporated on ultrafine branched TiO 2 NB. • The heterojunction greatly promotes the transfer of the photogenerated carriers. • ZnIn 2 S 4 /TiO 2 NFB exhibits photoinduced CP performance for metals in NaCl solution. [Display omitted] Boosting the photoinduced cathodic protection (CP) for metals in NaCl solution is crucial for achieving the application of photoelectrochemical conversion in marine corrosion protection. An environmentally friendly three-dimensional ZnIn 2 S 4 /TiO 2 nanoflowerbush (NFB) photoelectrode was constructed with sufficient interfacial incorporation based on the ultrafine branched TiO 2 nanobush substrate via a facile in situ hydrothermal method. This ZnIn 2 S 4 /TiO 2 NFB nanoheterojunction composite behaves excellent photoinduced CP performance for metallic materials. This is owing to the optimized construction of photoelectrode with relatively negative band potential, wide solar spectrum response, effective generation and collection of photoinduced electrons. The morphology, distribution and performance of ZnIn 2 S 4 vary with different substrates. The pure ZnIn 2 S 4 powder is nanoflower sphere composed of a lot of thin petals; when ZnIn 2 S 4 grow onto the FTO glass, the ZnIn 2 S 4 petals are distributed vertically on the two-dimensional structure; when ZnIn 2 S 4 grow on the three-dimensional ultrafine branched TiO 2 nanobush substrate, a ZnIn 2 S 4 /TiO 2 NFB architecture with ultrafine TiO 2 branchlet cores are formed. This ZnIn 2 S 4 /TiO 2 NFB photoelectrode can achieve efficient photoinduced CP performance for pure copper and low alloy steels with different negative self-corrosion potentials, such as Cu (−0.18 V), E40 (−0.45 V), Q345 (−0.55 V) and Q235 carbon steel (−0.65 V) under simulated sunlight irradiation in NaCl solution without additional hole scavengers, and the photoinduced CP current densities reach as high as 170, 72, 63 and 44 μA cm−2, respectively. The high-efficiency photoinduced CP performance is closely related to the band structure gradient matching between the TiO 2 and ZnIn 2 S 4 , prompting both the widened absorption of solar spectrum and high-efficiency transfer of the photogenerated electron–hole pairs. Importantly, the negative band potential of ZnIn 2 S 4 endues a lower surface work function which benefits the electron transport to the under-protected metallic materials to achieve photoinduced CP. This photoelectrode exhibits huge photoinduced CP application potential in marine environments. [ABSTRACT FROM AUTHOR]

• TiO 2 /MgTi x O y multiphase-heterojunction film was successfully prepared. • SKP is used to measure the surface work function of the photoelectrodes. • TiO 2 /MgTi x O y exhibits significantly enhanced PECCP Performance. • TiO 2 /MgTi x O y shows high PECCP stability. • The mechanism of TiO 2 /MgTi x O y multiphase heterojunctions for PECCP is proposed. Heterojunction engineering, as a rising star in the photoelectrochemical cathodic protection (PECCP) field, contributes to promote the separation of the photoinduced electrons and holes. In this paper, the TiO 2 /MgTi x O y multiphase-heterojunction film was prepared and its PECCP performance was studied. Due to a good energy band alignment gradient formed between the multiphases, the separation efficiency of the photoinduced electrons and holes generated by TiO 2 /MgTi x O y are dramatically enhanced, leading to its good PECCP performance and high stability. SKP is, for the first time, used to study the surface work function of the TiO 2 /MgTi x O y multiphase-heterojunction film for characterizing its PECCP performance. [ABSTRACT FROM AUTHOR]