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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第01期 139-156页

作者： H.HOSSEINI O.BALILASHAKI department of Mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

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Hybrid Kalman and unscented Kalman filters for INS/GPS integrated system considering constant lever arm effect

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Journal of Central South University 2015年第2期22卷 575-583页

作者：常国宾柳明 Tianjin Institute of Hydrographic surveying and Charting department of Navigation engineering Naval University of Engineering Key Laboratory of Aviation Information Technology in Universities of Shandong Binzhou University

In inertial navigation system(INS) and global positioning system(GPS) integrated system, GPS antennas are usually not located at the same location as the inertial measurement unit(IMU) of the INS, so the lever arm effect exists, which makes the observation equation highly nonlinear. The INS/GPS integration with constant lever arm effect is studied. The position relation of IMU and GPS's antenna is represented in the earth centered earth fixed frame, while the velocity relation of these two systems is represented in local horizontal frame. Due to the small integration time interval of INS, i.e. 0.1 s in this work, the nonlinearity in the INS error equation is trivial, so the linear INS error model is constructed and addressed by Kalman filter's prediction step. On the other hand, the high nonlinearity in the observation equation due to lever arm effect is addressed by unscented Kalman filter's update step to attain higher accuracy and better applicability. Simulation is designed and the performance of the hybrid filter is validated.

关键词： inertial navigation system global positioning system(GPS) integrated system lever arm effect Kalman filter unscented Kalman filter

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Digital close-range photogrammetric application to small-scale physical simulation experiment

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中国有色金属学会会刊：英文版 2011年第S3期21卷 681-685页

作者： LI Chun-yi1, CUI Xi-min2, YU Yi-ju3 1. School of surveying and Landing Information engineering, Henan Polytechnic University, Jiaozuo 454003, China 2. College of Geoscience and surveying engineering, China University of Mining and Technology, Beijing 100083, China 3. surveying and Mapping Press, Beijing 100045, China [a] School of surveying and Landing Information engineering Henan Polytechnic University Jiaozuo 454003 China [b] College of Geoscience and surveying engineering China University of Mining and Technology Beijing 100083 China [c] surveying and Mapping Press Beijing 100045 China

In order to research the possibility of digital close-range photogrammetric surveying in small scale physical simulation experiment, physical model coinciding with engineering practice was constructed based on similar theory. The datum processing method and surveying precision of digital close-range photogrammetric were analyzed. And the function relationship between overburden subsidence factor qr and the ratio z/H of stratum horizon z and mining depth H was researched. The results show that surveying points position mean error along horizontal direction is ±0.131 mm and vertical direction is ±0.192 mm. Therefore, multi-taking station cross direction digital close-range photogrammetric can completely satisfy the precision need of physical simulation experiment. And the empirical formula can be utilized to represent evolution law of stratum subsidence factor.

关键词： close-range photogrammetric physical simulation light-rays adjustment surveying precision subsidence factor

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Multi-verse Optimizer with Rosenbrock and Diffusion Mechanisms for Multilevel Threshold Image Segmentation from COVID-19 Chest X-Ray Images

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Journal of Bionic engineering 2023年第3期20卷 1198-1262页

作者： Yan Han Weibin Chen Ali Asghar Heidari Huiling Chen department of Computer Science and Artificial Intelligence Wenzhou UniversityWenzhou325035China School of surveying and Geospatial engineering College of EngineeringUniversity of TehranTehranIran

Coronavirus Disease 2019(COVID-19)is the most severe epidemic that is prevalent all over the *** quickly and accurately identifying COVID-19 is of great significance to controlling the spread speed of the ***,it is essential to accurately and rapidly identify COVID-19 lesions by analyzing Chest X-ray *** we all know,image segmentation is a critical stage in image processing and *** achieve better image segmentation results,this paper proposes to improve the multi-verse optimizer algorithm using the Rosenbrock method and diffusion mechanism named *** utilizes RDMVO to calculate the maximum Kapur’s entropy for multilevel threshold image *** image segmentation scheme is called *** ran two sets of experiments to test the performance of RDMVO and ***,RDMVO was compared with other excellent peers on IEEE CEC2017 to test the performance of RDMVO on benchmark ***,the image segmentation experiment was carried out using RDMVO-MIS,and some meta-heuristic algorithms were selected as *** test image dataset includes Berkeley images and COVID-19 Chest X-ray *** experimental results verify that RDMVO is highly competitive in benchmark functions and image segmentation experiments compared with other meta-heuristic algorithms.

关键词： COVID-19 Multilevel threshold image segmentation Kapur’s entropy Multi-verse optimizer Meta-heuristic algorithm Bionic algorithm

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Modelling extraordinary floods and sedimentological processes in a large channel-floodplain system of the Lower Paran River(Argentina)

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International Journal of Sediment Research 2015年第2期30卷 150-159页

作者： Marina L.Garcia Pedro A.Basile Gerardo A.Riccardi José F.Rodriguez Hydraulics department School of Civil EngineeringFaculty of Exact SciencesEngineering and Land SurveyingNational University of Rosario Centre for Hydro-Environmental Research Faculty of Exact SciencesEngineering and Land SurveyingNational University of Rosario Research Council of National University of Rosario(CIUNR) Civil Surveying and Environmental EngineeringUniversity of Newcastle

A quasi-2D unsteady flow and sediment transport model suitable for the simulation of large lowland river systems,including their floodplains,is *** water flow and sediment equations are discretised using an interconnected irregular cells scheme,in which different simplifications of the 1D de Saint Venant equations are used to define the discharge laws between ***-distributed transport and deposition of fine sediments throughout the river-floodplain system are *** model is applied over a 208-km reach of the Parana River between the cities of Diamante and Ramallo（Argentina） comprising a river-floodplain area of 8100 km;.After calibration and validation,the model is applied to predict water and sediment dynamics during synthetically generated extraordinary floods of100,1000,and 10,000 years return *** potential impact of a 56-km long road embankment constructed across the entire floodplain is simulated and compared to model results without the *** embankment results in increases in upstream water levels,inundation extent,flow duration,and sediment deposition.

关键词： Fluvial hydraulics Numerical modelling Floodplain sedimentation Lowland rivers Parana River

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Coulomb stress and gravity changes associated with the 2016 Mw 7.8 Kaikoura Earthquake, New Zealand: Application for aftershock triggering and fault interaction process analysis

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Journal of Mountain Science 2021年第2期18卷 510-527页

作者： HASSAN Abubakr HUANG Ding-fa JIANG Zhong-shan ZHANG Lu-peng Faculty of Geosciences and Environmental engineering Southwest Jiaotong UniversityChengdu 611756China surveying engineering department Faculty of EngineeringKarary UniversityKhartoum 12304Sudan

The Kaikoura earthquake on November 14,2016 is one of the largest and most complex earthquakes in New Zealand since *** the fact that it has ruptured about 12 separate faults,triggered 2132 aftershocks within one week of the mainshock and induced considerable stress changes,few studies have been conducted to comprensively investigate the *** current study examines the horizontal and vertical displacements as well as the stress and gravity changes,aftershock distributions and also find out whether these changes affect the surrounding regions along the complex fault *** study covers the entire area affected by the Kaikoura event,which includes the northern part of the South Island and the southern part of the North *** dislocation theory was employed to evaluate the coseismic slip model on the multiple *** displacement results revealed that the maximum horizontal displacement is about 6 m and the vertical about 2 m,which are reasonably consistent with earlier study ***,the stress and gravity changes are quite complicated and inhomogeneous as evidenced by our coseismic model,demonstrating the complexity of the Kaikoura earthquake as *** all the aftershocks are distributed in places where the stress and gravity change are found to be *** order to investigate the stability of our stress change models,we applied different friction coefficients and receiver fault *** results justify the friction coefficient(μ=0.4)and the receiver fault parameters(230°,70°,150°)are suitable to define good stress change *** to the stress change results at 15 km depth,the northern parts of the mainshock region,Hundalee fault,Humps fault and Jordan thrust areas together with the Wellington area are closer to failure and situated in a seismic risk *** multidimensional analysis adopted in this paper is helpful for making decisions and applications of stress and gravity change models in

关键词： Aftershock triggering Components displacement Coulomb failure stress Fault interaction Gravity change Kaikoura earthquake

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Novel Methodologies for Preventing Crack Propagation in Steel Gas Pipelines Considering the Temperature Effect

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Structural Durability & Health Monitoring 2025年第1期19卷 1-23页

作者： Nurlan Zhangabay Ulzhan Ibraimova Marco Bonopera Ulanbator Suleimenov Konstantin Avramov Maryna Chernobryvko Aigerim Yessengali department of Architecture and Urban Planning Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan department of Industrial Civil and Road Construction Mukhtar Auezov South Kazakhstan UniversityShymkent160012Kazakhstan Mechanics Sound&Vibration LaboratoryDepartment of Civil EngineeringCollege of EngineeringNational Taiwan UniversityTaipei10617Taiwan department of Reability&Dynamic Strength A.Pidhornyi Institute of Mechanical Engineering Problems of National Academy of Sciences of UkraineKharkiv61046Ukraine

Using the software ANSYS-19.2/Explicit Dynamics,this study performedﬁnite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crack,strengthened by steel wire *** effects of the thread tensile force of the steel winding in the form of single rings at the crack edges and the wires with different winding diameters and pitches were also *** results showed that the strengthening was preferably executed at a minimum value of the thread tensile force,which was 6.4%more effective than that at its maximum *** analysis of the inﬂuence of the winding dia-meters showed that the equivalent stresses increased by 32%from the beginning of the crack growth until the wire *** increment in winding diameter decelerated the disclosure of the edge crack and reduced its length by 8.2%.The analysis of the inﬂuence of the winding pitch showed that decreasing the distance between the winding turns also led to a 33.6%reduction in the length of the straight crack and a 7.9%reduction in the maximum stres-ses on the strengthened pipeline *** analysis of the temperature effect on the pipeline material,within a range from-40℃ to+50℃,resulted in a crack length change of up to 5.8%.As the temperature dropped,the crack length *** such a temperature range,the maximum stresses were observed along the cen-tral area of the crack,which were equal to 413 MPa at+50℃ and 440 MPa at-40℃.The results also showed that the presence of the steel winding in the pipeline signiﬁcantly reduced the length of crack propagation up to 8.4 times,depending on the temperature effect and design parameters of *** work integrated the existing methods for crack localization along steel gas pipelines.

关键词： Crack propagation ﬁnite-element internal pressure prestressing steel gas pipeline temperature effect

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VNLSTM-PoseNet: A novel deep ConvNet for real-time 6-DOF camera relocalization in urban streets

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Geo-Spatial Information Science 2021年第3期24卷 422-437页

作者： Ming Li Jiangying Qin Deren Li Ruizhi Chen Xuan Liao Bingxuan Guo State Key Laboratory of Information engineering in surveying Mapping and Remote Sensing Wuhan UniversityWuhanChina department of Physics ETH ZurichZurichSwitzerland department of Land surveying and Geo-informatics The Hong Kong Polytechnic UniversityHong KongChina

Image-based relocalization is a renewed interest in outdoor environments,because it is an important problem with many *** introduces Convolutional Neural Network(CNN)for the first time to realize the real-time camera pose solution based on a single *** order to solve the problem of precision and robustness of PoseNet and its improved algorithms in complex environment,this paper proposes and implements a new visual relocation method based on deep convolutional neural networks(VNLSTM-PoseNet).Firstly,this method directly resizes the input image without cropping to increase the receptive field of the training ***,the image and the corresponding pose labels are put into the improved Long Short-Term Memory based(LSTM-based)PoseNet network for training and the network is optimized by the Nadam ***,the trained network is used for image localization to obtain the camera *** results on outdoor public datasets show our VNLSTM-PoseNet can lead to drastic improvements in relocalization performance compared to existing state-of-theart CNN-based methods.

关键词： Camera relocalization pose regression deep convnet RGB image camera pose

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Development of a nomogram for overall survival in patients with esophageal carcinoma:A prospective cohort study in China

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World Journal of Gastrointestinal Oncology 2025年第1期17卷 158-168页

作者： Shi-Shi Yu Xi Zheng Xiao-Sheng Li Qian-Jie Xu Wei Zhang Zhong-Li Liao Hai-Ke Lei department of Gastroenterology Chongqing University Cancer HospitalChongqing 400030China Chongqing Cancer Multi-omics Big Data Application engineering Research Center Chongqing University Cancer HospitalChongqing 400030China department of Health Statistics School of Public HealthChongqing Medical UniversityChongqing 400016China

BACKGROUND Esophageal carcinoma(EC)presents a significant public health issue in China,with its prognosis impacted by myriad *** creation of a reliable prog-nostic model for the overall survival(OS)of EC patients promises to greatly advance the customization of treatment *** To create a more systematic and practical model that incorporates clinically significant indicators to support decision-making in clinical *** This study utilized data from a prospective longitudinal cohort of 3127 EC patients treated at Chongqing University Cancer Hospital between January 1,2018,and December 12,*** the least absolute shrinkage and selection operator regression alongside multivariate Cox regression analyses helped pinpoint pertinent variables for constructing the *** efficacy was assessed by concordance index(C-index),area under the receiver operating characteristic curve(AUC),calibration curves,and decision curve analysis(DCA).RESULTS Nine variables were determined to be significant predictors of OS in EC patients:Body mass index(BMI),Karnofsky performance status,TNM stage,surgery,radiotherapy,chemotherapy,immunotherapy,platelet-to-lymphocyte ratio,and albumin-to-globulin ratio(ALB/GLB).The model demonstrated a C-index of 0.715(95%CI:0.701-0.729)in the training cohort and 0.711(95%CI:0.689-0.732)in the validation *** the training cohort,AUCs for 1-year,3-year,and 5-year OS predictions were 0.773,0.787,and 0.750,respectively;in the validation cohort,they were 0.772,0.768,and 0.723,respectively,illustrating the model's *** curves and DCA verified the model's predictive accuracy and net *** A novel prognostic model for determining the OS of EC patients was successfully developed and validated to help clinicians in devising individualized treatment schemes for EC patients.

关键词： Esophageal carcinoma High-risk factors Prognosis Overall survival Prediction model

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Influence of T6 heat treatment on A356 and A380 aluminium alloys manufactured by thixoforging combined with low superheat casting

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Transactions of Nonferrous Metals Society of China 2018年第3期28卷 385-392页

作者： Ridvan GECU Serhat ACAR Alptekin KISASOZ Kerem ALTUG GULER Ahmet KARAASLAN department of Metallurgical and Materials engineering Yildiz Technical UniversityDavutpasa Campus

The effects of T6 heat treatment on thixoforged A356 and A380 aluminium alloys were *** superheat casting(LSC)technique was carried out to prepare proper specimens for thixoforging *** samples were poured at 20°C above their liquidus temperatures which provided the formation of equiaxed grains instead of dendritic *** billets were reheated for varied time from 20 to 80 min and thixoforged with 50%deformation *** thixoforging process,the samples were T6 heat treated for both A356 and A380 *** microstructural evaluation and hardness alteration of thixoforged,solution treated and aged specimens were examined comparatively by using optical microscopy,scanning electron microscopy with energy-dispersive X-ray spectroscopy and Brinell hardness equipment.T6 heat treatment provided relatively uniform microstructure with newly formed precipitates that are Mg2Si and Al2Cu for A356 and A380 billets,***,hardness after artificial aging was increased considerably and reached HB 93 for A356 and HB 120 for A380 alloys.

关键词： T6 heat treatment thixoforging low superheat casting aluminium alloy

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