Longitudinal Tearing Research Articles

Deep encoder-decoder networks for belt longitudinal tear detection

The belt conveyor is susceptible to longitudinal tearing, which poses a serious threat to the safety of coal mines. Traditional methods for detecting longitudinal tears have limitations such as poor image quality, limited applicability, and high hardware costs. An improved encoder-decoder network was proposed to solve the longitudinal tear detection problem. This method utilizes a line structured light system for image acquisition. The input images are downscaled using a sorting algorithm to extract the information of pixels with high grayscale values as the input feature map for the neural network. The reduced-dimensional encoder-decoder network then semantically segments the input feature map, and the resulting pixel segmentation is mapped to the location of the longitudinal tear. Finally, the position and length of the tear are calculated by back-projecting the semantic segmentation result to the world coordinate system. Experimental results demonstrate that this method effectively reduces hardware resource consumption and improves detection speed. The DICE and MIOU scores for the improved network are 97.69% and 95.47%, respectively, while the recall and precision for improved detection are 96.60% and 95.67%, respectively. Therefore, this method can successfully monitor longitudinal tear failures and ensure the safety of transportation.

Detection of three-dimensional belt deviation and longitudinal tearing defects based on binocular line laser technology

Detection of three-dimensional belt deviation and longitudinal tearing defects based on binocular line laser technology

Assessing damage degree of solid rocket motor under various cook-off conditions

This research is focused to investigate the cook-off response of a solid rocket motor (SRM) utilizing ammonium perchlorate/hydroxyl‑terminated polybutadiene (AP/HTPB) propellants under various heating environments, also assessing the damage degree of the motor casing and exploring the formation mechanism of ignition site. We have developed a three-dimensional (3-D) numerical model that encapsulates a range of response behaviors, including cook-off and mechanical destruction of the SRM. This model integrates multi-step thermal decomposition and combustion reaction models for the propellant, as well as a damage response model for the SRM. The response mechanisms of the SRM under varying thermal conditions have been simulated using a validated model. The study reveals that under both fast cook-off condition (FCC) and slow cook-off condition (SCC), the motors experienced deformation and rupture. Under FCC, ignition initiated at the motor head, reaching a maximum pressure of approximately 800 MPa near the ignition point. This led to the separation of the motor head from the main body, producing numerous casing fragments with the fragment cloud's radius showing a linear correlation to time (R = 0.73289t + 28.24286). The ignition delay was 224.5 s at an ignition temperature of 551.83 K. In contrast, under SCC, ignition occurred at the propellant's midsection inner surface, with a significantly lower maximum pressure of about 700 MPa. The motor expanded at this site, with the expansion radius exhibiting a nonlinear relationship to time (R = 0.19102t2 + 0.0096t + 32.97464). The casing then ruptured, causing extensive damage to both ends and generating a debris cloud with a radius that correlated linearly to time (R = 0.82147t + 26.70826). More severe longitudinal tearing, exceeding the FCC scenario, appeared in the motor body. The ignition delay time was 18.82 h. with an ignition temperature of 557.49 K.

Effect of quantitative feed restriction and sex class on sheep skin quality.

The aim was to evaluate the quality of the sheep skin of different sex classes submitted to different levels of feed restriction. Sheep without defined racial pattern of different sex classes (15 non-castrated males, 15 castrated males and 15 females), with initial body weight of 18.1 ± 0.4kg and mean age of 90days were distributed in a factorial 3 × 3, with three sex classes and 3 levels of feed restriction (ad libitum intake and restricted intake at 70 and 80%), with 5 repetitions. After slaughter, the skins were collected for physical-mechanical tests. The effect of the sex classes x levels of dietary restriction interaction was observed for transverse thickness and longitudinal rupture elongation (p < 0.05). Animals fed ad libitum had greater longitudinal transverse thickness (p < 0.05). Animals fed ad libitum and 70% feed restriction showed greater transverse elongation at break (p < 0.05). As for the difference between sex classes in the transverse thickness variable for tearing strength, the interaction sex classes x levels of feed restriction for transverse thickness, longitudinal thickness, transverse tearing strength and longitudinal tearing strength occurred (p < 0.05). Feed restriction reduces the physical quality of the skin of sheep of different sex classes, and the use of castrated male sheep in positive energy balance is recommended to obtain leather with greater thickness, longitudinal rupture elongation and transverse tear strength.

Experimental study on axial compression behavior of square pultruded GFRP tubular stub column

To investigate the influence of aspect ratio and width-to-thickness ratio on the axial compression behavior of square pultruded glass fiber-reinforced polymer (GFRP) tubular stub columns, axial compression tests were conducted on 12 GFRP tubular columns. The mechanical properties of the GFRP tubular columns, including load-bearing capacity, initial stiffness, compressive toughness, and ductility coefficient, were analyzed. The test results reveal that all GFRP tubular columns exhibit crushing failure, with specific failure modes, including mid-section fracture and longitudinal tearing along the corners of the columns. The load-bearing capacity is negatively correlated with the aspect ratio and width-to-thickness ratio. The initial stiffness negatively correlates with the aspect ratio, and the compressive toughness negatively correlates with the width-to-thickness ratio. The Hashin damage criteria for the C3D8R solid element was developed by utilizing the explicit finite element subroutine ABAQUS-VUMAT to analyze the axial compression behavior of GFRP tubular columns. Through parameter analysis, the relationship between the load-bearing capacity and fiber orientation was obtained, and an empirical equation for predicting the load-bearing capacity of the GFRP tubular column was proposed.

Hazard source detection of longitudinal tearing of conveyor belt based on deep learning.

Belt tearing is the main safety accident of belt conveyor. The main cause of tearing is the doped bolt and steel in the conveying belt. In this paper, the bolt and steel are identified as the Hazard source of tear. In this paper, bolt and steel are defined as the risk sources of tearing. Effective detection of the source of danger can effectively prevent the occurrence of conveyor belt tearing accidents. Here we use deep learning to detect the hazard source image. We improved on the SSD(Single Shot MultiBox Detector) model. Replace the original backbone network with an improved Shufflenet_V2, and replace the original position loss function with the CIoU loss function. Additionally, it compares this new approach to previous methods. The proposed model has surpassed other state-of-art methods with more than 94% accuracy. In addition, when deployed without GPU acceleration, the detection speed can reach 20fps. It can meet the requirements of real-time detection. The experimental results show that the proposed model can realize the online detection of hazard sources, so as to prevent longitudinal tearing of conveyor belt.

Production of Paper Using Biopulping of Pineapple Leaves Fibers (PALF) Followed by Chemical and Xylanase-Enzymatic Processing

ABSTRACT Pineapple leaf fibers (PALF) were biopulped using Trametes versicolor, and the resulting biopulp was bleached with xylanase-enzymatic treatments. The biopulping was extensively described using determinations of fiber morphology, color, chemical composition, extractive content, and thermal stability using the structural characteristics determined by XRD and paper properties. The results showed that the chemical and enzymatic treatments shortened the fiber, almost to 50%, and the Kappa index decreased from 27 to 13. Cellulose and holocellulose contents increased from 65% to 74% and from 86% to 91%, respectively, but extractives, lignin (from 12% to 4%), pentosans (from 25% to 14%) and the crystallinity decreased from 58% to 67% in both chemical bleaching and further xylanase-enzymatic processing. Xylanase-enzymatic processing allowed us to obtain whiter (increased lightness color and decreased redness and yellowness tonality) and heavier paper, even though it presented decreased mechanical properties (decreased stress resistance, rupture length, tear resistance and index longitudinal tearing). The xylanase-enzymatic treatment with the best pulping and paper properties is when the biopulp is treated with a xylanase enzyme concentration of 0.04% (w/w).

Geochemistry and geochronology of the Miocene adakite-like potassic dikes in Tethyan Himalaya: New insights into Indian lithosphere slab tearing and breakoff

Adakitic and potassic magmatic rocks are widespread in the Himalaya and the Tibetan Plateau, and their petrogenesis might provide potential insights into the deep crustal processes. However, the detailed spatiotemporal distributions of these rocks and their controlling mechanisms remain ambiguous. Here we report geochemical data, zircon U-Pb ages and Hf isotopic compositions of east-west (E-W) directed Qunrang monzonite porphyry dikes located in the Tethyan Himalaya. These rocks are acid and potassic with low Mg, low abundances of compatible elements, low Y and HREE, but with high Al, high Sr (822–1386 ppm) and Ba (2027–6091 ppm), high Th (62–84 ppm), U (9–16 ppm) and Th/U ratios (4–7), and thus high Sr/Y and (La/Yb)N ratios. The above geochemical features, combined with their negative whole-rock εHf(t) values (−3.9 to −4) and negative to small positive zircon εHf(t) values (−7.2 to +0.5), suggest that they were derived from partial melting of a thickened lower continental crust consisting mainly of garnet-amphibolite which were triggered and hybridized by underplating enriched mantle-derived shoshonitic melts. Zircon U-Pb ages of the Qunrang monzonite porphyry yielded a weighted mean age of 10.02 ± 0.33 Ma. Based on these observations, synthesized with the spatiotemporal distribution of the Oligocene-Miocene adakitic and potassic rocks in the southern Tibet, we propose that lateral detachment and longitudinal tearing processes might be potentially accounted for the eastward and southward younging trend of these magmatic rocks, whereas slab rollback and hinge advance might result in the unique E-W directed Qunrang adakite-like potassic dikes and the northward reversal younging trend.

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.

Arthroscopic Caudal Cruciate Ligament Damage in Canine Stifles with Cranial Cruciate Ligament Disease.

The aim of this study was to describe the arthroscopic changes to the caudal cruciate ligament (CdCL) in dogs with cranial cruciate ligament disease. Arthroscopic video recordings (n = 117) of the stifle with cranial cruciate ligament disease were reviewed. The extent of CdCL tearing was described. Signalment, palpable stifle stability and the presence of a meniscal tear were recorded. Pathology of the synovial joint and the synovium overlying the CdCL were scored at two time points.Two-way interactions were investigated (p < 0.05). Univariate analysis and a Wald test (p < 0.20) were performed. Factors were retained with a Wald test p < 0.05 or if a confounder, then a changing model coefficient >15%. A weighted kappa statistic was used to evaluate intraobserver agreement. Caudal cruciate ligament tearing was identified in 94% of stifles. Longitudinal tearing (76%) was the most common type of damage (45% partial, 31% full thickness). Synovitis was present in all joints and changes to the synovium overlying the CdCL were less frequently identified (67%).Synovitis was associated with the degree to CdCL tearing. Synovitis overlying the CdCL was associated with lower body weight and lower CdCL damage. Caudal cruciate ligament damage is common in dogs with cranial cruciate ligament disease and longitudinal tearing was the most common injury identified. Severity of joint pouch synovitis was positively correlated with the degree of CdCL damage and the portion of the CdCL not exposed to the synovium was unaffected. These findings suggest synovitis is likely a contributor to CdCL injury.

Three new species of Eugenia (Myrtaceae) from the Atlantic Forest of southeastern Brazil

Three new species of Eugenia from the Atlantic rainforest of southeastern Brazil are here described, illustrated and compared with morphologically similar species. Additionally, a distribution map is provided and preliminary conservation statuses are proposed. Eugenia cabofriana can be recognized by its tomentose young shoots and leaves, fasciculiform inflorescences, tomentose pedicels and ovary, and glabrous calyx. Eugenia longimitra is remarkably distinctive due to its auxotelic and racemiform inflorescences, and flower buds with a rostrate apiculum, which at anthesis opens often through a calyptra or sometimes by irregular longitudinal tearing in two halves. Eugenia pachypoda can be recognized mainly by its leaves with adaxially biconvex midvein, petioles absent or up to 2 mm long, leaf bases obtuse or cordiform, pedicels corky and detaching in thin, longitudinal plates, and flower buds with the calyx visibly less pilose than the ovary.

Effect of Micro- and Macro-Mechanical Characteristics of Jujube Bark on Jujube Girdling Quality

Jujube girdling is an important method to improve the yield and quality of jujube fruit. However, girdling usually causes the tearing of jujube bark, resulting in the slow healing and even death of jujube trees. These problems directly affect the economic benefits of jujube planting. In this paper, in order to reveal the tearing mechanism of jujube bark caused by girdling, and provide the basic mechanical parameters of jujube bark for the research and development of automatic girdling equipment, the structure and mechanical characteristics of jujube bark were studied through theory and experimental methods. The results of microscopic observation showed that jujube bark is a biological composite material mainly composed of the phloem, periderm and epidermis. Furthermore, a mathematical model-based analysis of the growth stress of jujube bark showed that growth stress can be regarded as a biaxial stress state, which can promote the longitudinal tearing of jujube bark during girdling. The tensile test results of jujube bark showed that jujube bark belongs to the category of anisotropic and biologic material. Its longitudinal and transverse mechanical characteristics are significantly different. The maximum longitudinal tensile load was in the range of 105.9~293 N, the longitudinal tensile strength was 16.3 MPa and the elastic modulus was 255.6 MPa. The average transverse tensile load was only 27.9% of the longitudinal tensile load. The transverse tensile strength was 3.5 Mpa and its elastic modulus was 724.14 MPa. The transverse cutting test of jujube bark showed that the average cutting force was 118.2 N and the cutting strength was 9.8 MPa. The results of this study showed that both the growth stress and the anisotropic natural polymer of jujube bark have adverse effects on girdling. Subsequently, issues relating to the selection of appropriate girdling tools and the matters needing attention in the process of the girdling operation were proposed, so as to guide the correct application of girdling technology. In addition, some suggestions on the research and development of girdling tools in the future are put forward.

Research on a sound-based method for belt conveyor longitudinal tear detection

Aiming at the problems of accuracy, non-real-time performance, poor reliability and high complexity in belt conveyor longitudinal tearing detection, a belt conveyor longitudinal tearing detection method based on sound is proposed. The sound signals of belt conveyors are collected using a sound acquisition processor. First, the sound signal is processed by a preprocessing algorithm. The characteristics of the processed sound signal are extracted using the LFCC and GFCC combined with a feature extraction algorithm. The feature data of the sound signal are divided into a training set and a test set. The parameters of the convolutional neural network are improved by training and optimization of the training set data. Finally, a convolutional neural network model of the sound signal characteristics of a belt conveyor is obtained. The model is used to classify and identify the longitudinal tearing sound signals of the test set. The experimental results show that this method can realize the identification and detection of the longitudinal tearing sound of a belt conveyor. The average accuracy of the detection is above 94%, and the average processing time is 21.6 ms. The detection range is large, the cost is low, and the accuracy, real-time performance and reliability are high, which meets the requirements of longitudinal tear detection.

Sound-Based Improved DenseNet Conveyor Belt Longitudinal Tear Detection

At present, conveyor belt tearing is the most serious fault of belt conveyor, causing the greatest loss. This paper aims to overcome the issues of poor accuracy, low precision, and poor real-time performance in the longitudinal tear detection of the conveyor belt of the belt conveyor. Specifically, this paper presents a method of longitudinal tear detection of conveyor belt based on the sound signal. According to the recognition of the tearing sound signal, the longitudinal tearing of conveyor belt can be detected. A dynamic MFCC feature extraction method is proposed to extract the sound signal feature. An improved DenseNet neural network model is designed, which is used to classify the longitudinal sound of the belt conveyor to realize the longitudinal tearing detection of the conveyor belt.The experimental results demonstrate that the method in this paper achieves the sound detection of the longitudinal tear of the conveyor belt, and the average accuracy of the longitudinal tear detection of the conveyor belt of the belt conveyor reaches 95.42%, which satisfies the requirements of the longitudinal tear detection of the conveyor belt of the belt conveyor.Applying this method to the longitudinal tearing detection of conveyor belt can solve the shortcomings of existing methods and realize the detection of the longitudinal tearing fault of conveyor belt.

Research on belt tear detection algorithm based on multiple sets of laser line assistance

Conveyor is mainly used for ore collection and transportation, and it plays an important role in mining operations. Due to the harsh mining environment, the conveyor belt often has longitudinal tear. If the tears can not be found in time, a safety accident will occur and cause significant economic losses. In order to accurately and efficiently detect the longitudinal tearing of the conveyor belt, this paper proposes a computer vision detection algorithm based on multiple sets of lasers. This algorithm can accurately segment the laser stripe area through image processing and analysis, and accurately locate the torn area of the conveyor belt. And this method supports users to customize the alarm level of tear detection, which meets different industrial production scenarios. The experimental results show that the method proposed in this paper can accurately and quickly detect the longitudinal tearing defect of the conveyor belt.

Infrared spectrum analysis method for detection and early warning of longitudinal tear of mine conveyor belt

• Monitor longitudinal tear with infrared thermography. • Overcome the interference caused by the change of infrared image threshold. • Select the appropriate detection spectral passband. • Coefficient T can be used to quantitatively describe tear change characteristics. A novel approach based on infrared spectrum analysis for early-warning of longitudinal tearing of the conveyor belt was proposed in the paper. Unlike most existing methods, the proposed method monitors the change process of the infrared radiation field of the longitudinal tearing through the infrared thermal imaging technology, and judges whether there is the risk of the longitudinal tearing of the conveyor belt through the frequency-domain characteristic coefficient T of the infrared radiation field. Experimental results exhibit that the characteristic coefficient T can quantitatively describe the change characteristics of infrared radiation field during the tearing process of conveyor belt. When the conveyor belt is complete penetration, the T value fluctuates violently from 0.6 to 1.6. This characteristic can be used as the precursor information of the tearing process, which broadens the train of thought for identification and early warning of conveyor belt longitudinal tearing.

Longitudinal tear early-warning method for conveyor belt based on infrared vision

Longitudinal tear of the conveyor belt is a serious threat to the safe operation of the belt conveyor. To address this problem, a novel approach based on infrared vision for early-warning of longitudinal tearing of the conveyor belt was proposed in the paper. Unlike most existing methods, the proposed approach captures images of the conveyor belt only by one infrared camera and judges whether the conveyor belt is at the risk of longitudinal tearing based on the connected components detection result. The method first performs image filtering, ROI selection and image binarization on the infrared image. Then, it is determined by the number of connected components detection whether the early-warning should be issued. Experimental results exhibit that the average detection accuracy of the longitudinal tear early-warning based on our method can reach 99.19%. The method processes an infrared image for less than 6 ms, which can meet the real-time system requirements.

Multispectral visual detection method for conveyor belt longitudinal tear

As an important part of modern coal mine production, conveyor belts are widely used in the coal collection and transportation. In order to ensure the safe operation of the coal mine conveyor belt and solve the drawbacks of the existing conveyor belt longitudinal tear detection technology, a multispectral visual detection method for conveyor belt longitudinal tear is proposed in this paper. The experimental results show that the multispectral visual detection method not only can identify the conveyor belt longitudinal tear, but also accurately classifies and identify other states of the conveyor belt. The accuracy of multispectral visual detection method is over 90.06%, and the precision of longitudinal tearing recognition is over 92.04%. The proposed method is verified to meet the requirements of reliability and real-time in the industrial field.

Planar Porous Graphene Woven Fabric/Epoxy Composites with Exceptional Electrical, Mechanical Properties, and Fracture Toughness.

Planar interconnected graphene woven fabrics (GWFs) are prepared by template-based chemical vapor deposition and the GWFs are employed as multifunctional filler for epoxy-based composites. Apart from flexibility, transparency, lightweight, and high electrical conductivity, the GWFs have unique morphological features consisting of orthogonally interweaved, inherently percolated, hollow graphene tubes (GTs). The orthogonal GT structure means that the GWF/epoxy composites hold significant anisotropy in mechanical and fracture properties. The composites with 0.62 wt % graphene deliver a combination of excellent electrical and fracture properties: e.g., an electrical conductivity of ~0.18 S/cm; and fracture toughness of 1.67 and 1.78 MPa·m(1/2) when loaded along the 0° and 45° directions relative to the GT direction, respectively, equivalent to notable 57% and 67% rises compared to the solid epoxy. Unique fracture processes in GWF/epoxy composites are identified by in situ examinations, revealing crack tip blunting that occurs when the crack impinges GTs, especially those at 45° to the crack growth direction, as well as longitudinal tearing of hollow GTs as the two major toughening mechanisms.

Tensile strength of Z-pinned laminates in RTD and hot-wet environment

Abstract Experiments and simulation analysis for tensile strength of Z-pinned laminates were conducted in both room temperature and dry and hot-wet environments. The results of the experiments show that the fracture of [0]6 specimen with Z-pins was longitudinally torn, and there was a row of Z-pins at the fracture of [(±45)/(0,90)]2S specimen with Z-pins. It could be observed that the hot-wet effect on the tensile strength of the Z-pinned laminates increased with percentage of 0-direction fibers decreasing in the laminates from the experiments of the unidirectional tape laminates and the woven cloth laminates. When the volume content of Z-pin increased, the hot-wet effect on tensile strength of Z-pinned [45/0/-45/90]2S laminates with Z-pins would become smaller and smaller. The simulation method of the hot-wet effect on tensile strength of the laminates was combined with the experiment and the finite element analysis. It used 14 nonlinear springs to simulate the longitudinal tearing of [0]6 specimen with Z-pins. The simulation results showed that Z-pin played a role of fulcrum, and because of the lever principle, the fiber bundles were torn at both tips in resin-rich area.