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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]

• 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]