Application of YOLOv4 Algorithm for Foreign Object Detection on a Belt Conveyor in a Low-Illumination Environment

The most common failures of belt conveyors are runout, coal piles and longitudinal tears. The detection methods for longitudinal tearing are currently not particularly effective. A key study area for minimizing longitudinal belt tears with the advancement of machine learning is how to use machine vision technology to detect foreign items on the belt. In this study, the real-time detection of foreign items on belt conveyors is accomplished using a machine vision method. Firstly, the KinD++ low-light image enhancement algorithm is used to improve the quality of the captured low-quality images through feature processing. Then, the GridMask method partially masks the foreign objects in the training images, thus extending the data set. Finally, the YOLOv4 algorithm with optimized anchor boxes is combined to achieve efficient detection of foreign objects in belt conveyors, and the method is verified as effective.Transport Engineering and Logistic

Multi-Objective Parameter Optimization of Flexible Support System of Optical Mirror

During the processing of an optical mirror, the performance parameters of the bottom support system would affect the surface forming accuracy of the mirror. The traditional bottom support system has a large unadjustable support stiffness, which increases the difficulty of unloading the impact force generated by the grinding disc. In response to this scenario, a flexible support system (FSS) consisting of 36 support cylinders with beryllium bronze reeds (BBRs) and rolling diaphragms (RDs) as key components is designed. It is necessary to analyze the key components of the support cylinder to reduce its axial movement resistance, ensure a consistent force output of each support point. First, the internal resistance model of a flexible support cylinder is established, and the main factors of internal resistance are then analyzed. Thereafter, the multi-objective structural parameters of the BBR and RD are simulated in ANSYS using the control variable method. The optimal structural parameters of BBR and RD are determined by simulation. Finally, experiments are performed on the RD ultimate pressure, internal resistance of the support cylinder, and consistency of the force output of the FSS. The experimental results show that the support cylinder with the optimized design has good force output consistency, which provides a theoretical basis for the application of FSS in optical mirror processing.Transport Engineering and Logistic

Identifying and Characterizing Conveyor Belt Longitudinal Rip by 3D Point Cloud Processing

Real-time and accurate longitudinal rip detection of a conveyor belt is crucial for the safety and efficiency of an industrial haulage system. However, the existing longitudinal detection methods possess drawbacks, often resulting in false alarms caused by tiny scratches on the belt surface. A method of identifying the longitudinal rip through three-dimensional (3D) point cloud processing is proposed to solve this issue. Specifically, the spatial point data of the belt surface are acquired by a binocular line laser stereo vision camera. Within these data, the suspected points induced by the rips and scratches were extracted. Subsequently, a clustering and discrimination mechanism was employed to distinguish the rips and scratches, and only the rip information was used as alarm criterion. Finally, the direction and maximum width of the rip can be effectively characterized in 3D space using the principal component analysis (PCA) method. This method was tested in practical experiments, and the experimental results indicate that this method can identify the longitudinal rip accurately in real time and simultaneously characterize it. Thus, applying this method can provide a more effective and appropriate solution to the identification scenes of longitudinal rip and other similar defects.Transport Engineering and Logistic

IGA-Reuse-NET: A deep-learning-based isogeometric analysis-reuse approach with topology-consistent parameterization[Formula presented]

In this paper, a deep learning framework combined with isogeometric analysis (IGA for short) called IGA-Reuse-Net is proposed for efficient reuse of numerical simulation on a set of topology-consistent models. Compared with previous data-driven numerical simulation methods only for simple computational domains, our method can predict high-accuracy PDE solutions over topology-consistent geometries with complex boundaries. UNet3+ architecture with interlaced sparse self-attention (ISSA) module is used to enhance the performance of the network. In addition, we propose a new loss function that combines a coefficients loss and a numerical solution loss. Several training datasets with topology-consistent models are constructed for the proposed framework. To verify the effectiveness of our approach, two different types of Poisson equations with different source functions are solved on three datasets with different topologies. Our framework can achieve a good trade-off between accuracy and efficiency. It outperforms the physics-informed neural network (PINN for short) model and yields promising results of prediction.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Manufacturin

Combined effects of photoaging and natural organic matter on the colloidal stability of nanoplastics in aquatic environments

The transport and fate of nanoplastics (NPs) in aquatic environments are closely associated with their colloidal stability, which is affected by aging and natural organic matter (NOM) adsorption. This study systematically investigated the combined effects of photoaging and NOM (e.g. humic acids, HA; and a model protein, bovine serum albumin, BSA) on the aggregation kinetics of NPs (polystyrene, PS) in NaCl and CaCl2 solutions. Our results showed that photoaged NPs adsorbed less HA than pristine NPs due to weaker hydrophobic and π-π interactions. In return, HA showed weaker impacts on NPs’ stability after photoaging. Differently, photoaged NPs absorbed more BSA than pristine NPs due to stronger hydrogen bonding and electrostatic attraction. Thus, the inhibitory effects of BSA on the aggregation kinetics of NPs were enhanced after photoaging. Regarding the effects of NOM on the aging of NPs, our results showed that HA competed with NPs for photons and underwent photo-degradation. Subsequently, the destruction/reconstruction of adsorbed HA increased (in NaCl) or decreased (in CaCl2) the stability of NPs. Notably, light radiation-induced flocculation of BSA molecules, which wrapped and integrated NPs and lead to their destabilization. Overall, this study provided new insights into the aggregation behavior of NPs in aquatic systems, which have significant implications for predicting the transport and fate of NPs in complex real-world environments.Sanitary Engineerin

Engineering a lipase B from Candida antactica with efficient perhydrolysis performance by eliminating its hydrolase activity

A Ser105Ala mutant of the lipase B from Candida antarctica enables 'perhydrolase-only' reactions. At the example of the chemoenzymatic Baeyer-Villiger oxidation of cyclohexanone, we demonstrate that with this mutant selective oxidation can be achieved in deep eutectic solvent while essentially eliminating the undesired hydrolysis reaction of the product.BT/Biocatalysi

Manipulate energy transport via fluorinated spacers towards record-efficiency 2D Dion-Jacobson CsPbI₃ solar cells

Two-dimensional (2D) Dion-Jacobson (D-J)-type cesium lead iodide CsPbI 3 perform remarkably in terms of stability. However, the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells (PSCs). Herein, starting from the considerable structural diversity of organic spacers, we engineer 2D CsPbI 3 with fine-tuning functionalities. Specifically, for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI 3, and successfully applied it into construction of high-performance PSCs. Compared with constitutive 1,4-diaminobenzene (PDA), the fluorinated 2-fluorobenzene-1,4-diamine (F-PDA) component greatly expands the dipole moment from 0.59D to 3.47D, which reduces the exciton binding energy of the system. A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in (F-PDA)Cs n– 1Pb nI 3 n+ 1. The results show that (F-PDA)Cs n– 1Pb nI 3 n+ 1 demonstrates more significant charge transfer between organic and inorganic layers than (PDA)Cs n– 1Pb nI 3 n+ 1, and it is confirmed in the femtosecond transient absorption experiment. Moreover, the interactions of the fluorinated spacer with the [PbI 6] 4 – plane effectively manipulate the crystallization quality, and thus the ion migration and defect formation of target 2D CsPbI 3 are inhibited. As a result, we obtained a record power conversion efficiency (PCE) beyond 15% for 2D D-J (F-PDA)Cs 3Pb 4I 13 (n = 4) PSCs with significantly improved environmental stability compared with the three-dimensional (3D) counterparts. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Photovoltaic Materials and Device

Effects of wheat straw biochar on carbon mineralization and guidance for large-scale soil quality improvement in the coastal wetland

To study the effects of wheat straw and its biochar on carbon mineralization in saline soil, we investigated the changes of carbon (C) mineralization rate with different carbon sources under constant moisture (CM) and drying-rewetting (DW) cycles in a homoeothermic incubator. Six treatments including control (C), wheat straw (S+W), 300 degrees C wheat straw biochar (S+C-1), 600 degrees C wheat straw biochar (S+C-2), double 300 degrees C wheat straw biochar (S+2C(1)) and combination of wheat straw and its biochar (S+W+C-1) were evaluated in the present study. Application wheat straw to the soil resulted in the higher release of CO2 than that of the treatment of S+C-1 and S+C-2. However, the CO2 release of S+W+C-1 treatment was lower as compared to wheat straw alone, which can be ascribed to the higher adsorption of biochar for organic matter. Rewetting the dried treatments caused higher release of CO2 than that of CM, but the cumulative C mineralization of DW was less than that of CM in all treatments. The extent of reduction between DW and CM was less pronounced in S+2C(1) and S+W+C-1 especially with increasing DW cycles. The results suggested that the flush of mineralized C in rewetting period can be partly compensate for the reduction of mineralized C during the drying period. The fact can be explained by the good adjustability of "r-strategist" microbes in rewetting period and the provision of better physical habitats by biochar. In general, the stress of DW cycles on saline soils could be effectively reduced with biochar application especially with low charred temperature biochar. (C) 2013 Elsevier B.V. All rights reserved.To study the effects of wheat straw and its biochar on carbon mineralization in saline soil, we investigated the changes of carbon (C) mineralization rate with different carbon sources under constant moisture (CM) and drying-rewetting (DW) cycles in a homoeothermic incubator. Six treatments including control (C), wheat straw (S+W), 300 degrees C wheat straw biochar (S+C-1), 600 degrees C wheat straw biochar (S+C-2), double 300 degrees C wheat straw biochar (S+2C(1)) and combination of wheat straw and its biochar (S+W+C-1) were evaluated in the present study. Application wheat straw to the soil resulted in the higher release of CO2 than that of the treatment of S+C-1 and S+C-2. However, the CO2 release of S+W+C-1 treatment was lower as compared to wheat straw alone, which can be ascribed to the higher adsorption of biochar for organic matter. Rewetting the dried treatments caused higher release of CO2 than that of CM, but the cumulative C mineralization of DW was less than that of CM in all treatments. The extent of reduction between DW and CM was less pronounced in S+2C(1) and S+W+C-1 especially with increasing DW cycles. The results suggested that the flush of mineralized C in rewetting period can be partly compensate for the reduction of mineralized C during the drying period. The fact can be explained by the good adjustability of "r-strategist" microbes in rewetting period and the provision of better physical habitats by biochar. In general, the stress of DW cycles on saline soils could be effectively reduced with biochar application especially with low charred temperature biochar. (C) 2013 Elsevier B.V. All rights reserved

Integration into plant biology and soil science has provided insights into the total environment

The total environment includes 5 closely-linking circles, in which biosphere and lithosphere are the active core. As global population increases and urbanization process accelerates, arable land is gradually decreasing under global climate change and the pressure of various types of environmental pollution. This case is especially for China. Land is the most important resources for human beings' survival. How to increase and manage arable land is the key for sustainable agriculture development. China has extensive marshy land that can be reclamated for the better potential land resources under the pre- condition of protecting the environment, which will be a good way for enlarging globally and managing arable land. Related studies have been conducted in China for the past 30years and now many results with obvious practical efficiency have been obtained. For summarizing these results, salt-soil will be the main target and related contents such as nutrient transport, use types, biodiversity and interactions with plants from molecular biology to ecology will be covered, in which the interactions among biosphere, lithosphere, atmosphere and anthroposphere will be focused on. (C) 2016 Elsevier B.V. All rights reserved

A simulation of rill bed incision processes in upland concentrated flows

Quantifying rill bed incision provides fundamental information for process-based erosion modeling; while the morphodynamic and hydrodynamic mechanism in bed incision processes are still unclear. Thus, experiments were conducted to examine rill bed incision processes in upland concentrated flows. DEMs (2 mm x 2 mm resolution) obtained by photogrammetry were used for sill bed morphology analysis. Rill channel (2.0 m-long, 0.08 m-wide and 0.15 m-deep) with two slope gradients (15 degrees and 20 degrees) were subjected to four overland flow rates (1.0, 2.0, 3.0 and 4.0 L min(-1)). The results showed that sediment delivery, rill bed incision rate and average rill depth increased with inflow rate and bed slope. Sediment delivery increased from 0.060 to 0.226 kg min(-1) per 1 L min(-1) inflow increment and from 0.043 to 0.207 kg min(-1) when bed slope increased from 15 degrees to 20 degrees. In a well-developed rill channel, rill bed incision could be divided into three phases: pre-headcut formation (dominated by rill flow shear stress), headcut incision (dominated by headcut advancing) and post-headcut incision (dominated by rill flow shear stress). Headcut incision phase, which only accounted for 65% of rill bed sediment. In the pre-headcut formation phase, rill flow velocity, shear stress and stream power increased with increases of inflow rate and slope gradient. Conversely, flow velocity showed no evident trend with increased inflow rate and bed slope during headcut incision phase. Initial headcut advancing rate could be predicted by a non-linear function based upon soil characteristics, rill flow shear stress and headcut height. Sediment delivery showed a power function with the product of inflow rate and squared bed slope. Because rill bed incision is dominated by headcut advancement and incision, practices for controlling headcut initiation should be implemented to decrease hillslope soil loss