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perforation of the duodenum by an ingested toothbrush

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World Journal of Gastroenterology 2008年第27期14卷 4410-4412页

作者： Hsiao-Hsiang Chao Tzu-Chieh Chao Division of General Surgery Department of Surgery Chang Gung Memorial Hospital at Linkou Kweishan Department of Surgery Chang Gung Memorial Hospital at Linkou and Chang Gung University School of Medicine Kweishan

We report a rare case of duodenal perforation caused by an ingested 12-cm long toothbrush handle. A 22-year-old female presented with intermittent epigas- tric pain for 6 d after swallowing a broken toothbrush. The swallowed toothbrush could not be removed from the second portion of the duodenum by endoscopy. Laparotomy revealed a perforation in the anterior wall of the duodenal bulb. The toothbrush was removed via the perforation which was debrided and closed. There were no postoperative complications.

关键词： Duodenum Endoscopy Laparotomy perforation Toothbrush

perforation of small bowel caused by Schistosoma japonicum : A case report

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World Journal of Gastroenterology 2015年第9期21卷 2862-2864页

作者： Jin-Jian Xiang Ben-Jing Cheng Fu Tian Mi Li Xue-Feng Jiang Hui-Chuan Zhao Xiao-Miao Hu Bao-Lai Xiao Jian-Ping Xie Arpana Shrestha Department of General Surgery the First Hospital affiliated to Yangtze University Department of Pathology the First Hospital Affiliated to Yangtze University

A 67-year-old man from Jingzhou was admitted to the First Hospital Affiliated to Yangtze University in July 2013 with sudden onset of abdominal pain with dizziness for 12 *** patient had sign of peritoneal *** of the abdomen and pelvis showed hepatic fibrosis due to *** tomography showed free gas in the peritoneal *** abdominal radiography showed bilateral subdiaphragmatic accumulation of gas, perforation of the viscus, and radio-opacity in the left renal *** patient underwent emergency exploratory *** laparotomy, a moderate amount of muddy yellow pus was found in the intra-abdominal *** the junction of the jejunum and ileum, about 250 cm from Treitz's ligament, there was an about 10-cm length of inflamed small bowel with perforation(3 mm in diameter) along the mesenteric border at the middle of the *** patient underwent resection of the affected intestinal segment, along with end-to-end intestinal *** examination revealed mucosal necrosis and hemorrhage with a large number of infiltrating eosinophils and neutrophils, and acute submucosal inflammation with a large number of infiltrating eosinophils and neutrophils associated with Schistosoma japonicum(***) *** intravascular adult parasite was ***, the patient was treated with praziquantel(30 mg/kg daily) for 4 *** patient progressed *** the best of our knowledge, this is the first case of small bowel perforation associated with eggs of ***.

关键词： Schistosoma japonicum Intestinal perforation Small

perforation of levonorgestrel-releasing intrauterine system found at one month after insertion:A case report

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World Journal of Clinical Cases 2023年第1期11卷 172-176页

作者： Guo-Rui Zhang Xin Yu Department of Obstetrics and Gynecology State Key Laboratory of ComplexSevere and Rare DiseasesNational Clinical Research Center for Obstetric&Gynecologic DiseasesPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China

BACKGROUND The levonorgestrel-releasing intrauterine system(LNG-IUS)is widely used in contraception,menorrhagia,dysmenorrhea and to prevent endometrial hyperplasia during estrogen *** is more often seen after early postpartum *** of the LNG-IUS occurring one month after placement is *** SUMMARY A 42-year-old female complained of progressive dysmenorrhea and increased menstrual *** was diagnosed with adenomyosis and the LNG-IUS was inserted in her uterine *** ultrasound examination one month later revealed that the intra-uterine device(IUD)was not found in the uterine cavity,and further X-ray and pelvic magnetic resonance imaging showed an abnormal signal area in the left posterior region of the *** exploratory surgery was performed and the LNG-IUS was found in the left uterosacral *** perforation of a LNG-IUS occurring one month after placement is rare,and is more common in inexperienced operators and after early postpartum *** the operation is difficult,ultrasound monitoring is recommended to reduce the risk of IUD *** patients with inadequate surgery,postoperative imaging is recommended to detect potential risks as soon as possible.

关键词： Levonorgestrel-releasing intrauterine system perforation Malposition Case report

PREDICTION OF PROJECTILE PENETRATION AND perforation BY FINITE CAVITY EXPANSION METHOD WITH THE FREE-SURFACE EFFECT

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Acta Mechanica Solida Sinica 2014年第6期27卷 597-611页

作者： Qin Fang Xiangzhen Kong Jian Hong Hao Wu PLA University of Science and Technology

With a target treated as the incompressible Tresca and Mohr-Coulomb material, by assuming that cavity expansion produces plastic-elastic and plastic-cracked-elastic response region, the decay function for the free-surface effect is constructed for metal and geological tar- gets, respectively. The forcing function for oblique penetration and perforation is obtained by multiplying the forcing function derived on the basis of infinite target assumption with the de- cay function. Then the projectile is modeled with an explicit transient dynamic finite element code and the target is represented by the forcing function as the pressure boundary condition. This methodology eliminates discretizing the target as well as the need for a complex contact algorithm and is implemented in ABAQUS explicit solver via the user subroutine VDLOAD. It is found that the free-surface effect must be considered in terms of the projectile deformation, residual velocity, projectile trajectory, ricochet limits and critical reverse velocity. The numerical predictions are in good agreement with the available experimental data if the free-surface effect is taken into account.

关键词： penetration perforation finite spherical cavity expansion free-surface effect

Statistical variability and fragility assessment of ballistic perforation of steel plates for 7.62 mm AP ammunition

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Defence Technology（防务技术） 2020年第3期16卷 503-513页

作者： Mark G.Stewart Michael DNetherton Centre for Infrastructure Performance and Reliability The University of NewcastleNew South Wales2038Australia

The paper describes field test results of 7.62×51 mm M61 AP(armour piercing) ammunition fired into mild steel targets at an outdoor *** targets varied from 10 mm to 32 mm in *** tests recorded penetration depth,probability of perforation(i.e.,complete penetration),muzzle and impact velocities,bullet mass,and plate yield strength and *** measured penetration depth exhibited a variability of approximately±12%.The paper then compared ballistic test results with predictive models of steel penetration depth and thickness to prevent *** parameters were derived for muzzle and impact velocity,bullet mass,plate thickness,plate hardness,and model error.A Monte-Carlo probabilistic analysis was then developed to estimate the probability of plate perforation of 7.62 mm M61 AP ammunition for a range of impact velocities,and for mild steels,and High Hardness Armour(HHA) *** perforation fragility analysis considered the random variability of impact velocity,bullet mass,plate thickness,plate hardness,and model *** a probabilistic analysis allows for reliability-based design,where,for example,the plate thickness with 95% reliability(*** 1 in 20 shots will penetrate the wall) can be estimated knowing the probabilistic distribution of ***,it was found that the plate thickness to ensure a low 5% probability of perforation needs to be 11-15% thicker than required to have a 50/50 chance of perforation for mild steel *** would need to be 20-30% thicker if probability of perforation is reduced to zero.

关键词： Ballistics Probability Statistics Steel plates Armour steel Ammunition Experimental perforation

Effect of perforation on flow past a conic cylinder at Re =100: wavy vortex and sign laws

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Acta Mechanica Sinica 2018年第5期34卷 812-829页

作者： L.M.Lin X.F.Zhong Y.X.Wu Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

In order to find the intrinsic physical mechanism of the original Kármán vortex wavily distorted across the span due to the introduction of three-dimensional (3-D) geometric disturbances,a flow past a peak-perforated conic shroud is numerically simulated at a Reynolds number of *** on previous work by Meiburg and Lasheras (1988),the streamwise and vertical interactions with spanwise vortices are introduced and *** vortex-shedding patterns in the near wake for different flow regimes are reinspected and illustrated from the view of these two ***,in regime Ⅰ,spanwise vortices are a little distorted due to the weak *** in regime Ⅱ,spanwise vortices,even though curved obviously,are still shed synchronously with moderate streamwise and vertical *** in regime Ⅲ,violently wavy spanwise vortices in some vortex-shedding patterns,typically an Ω-type vortex,are mainly attributed to the strong vertical interactions,while other cases,such as multiple vortex-shedding patterns in sub-regime Ⅲ-D,are resulted from complex streamwise and vertical interactions.A special phenomenon,spacial distribution of streamwise and vertical components of vorticity with specific signs in the near wake,is analyzed based on two models of streamwise and vertical vortices in explaining physical reasons of top and bottom shear layers wavily varied across the *** these two models and above two interactions are *** two sign laws are summarized:the first sign law for streamwise and vertical components of vorticity is positive in the upper shear layer,but negative in the lower shear layer,while the second sign law for three vorticity components is always negative in the wake.

关键词： Vortex-shedding pattern Flow control Vortex dynamics Conic disturbance perforation Sign law

A study of the perforation of stiffened plates by rigid projectiles

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Acta Mechanica Sinica 2005年第6期21卷 582-591页

作者： Jianguo Ning Weidong Song Jing Wang State Key Laboratory of Explosion Science and TechnologyBeijing Institute of Technology Beijing 100081 China

In the present paper, a four-stage perforation model that accurately predicts the residual velocity is developed by adopting an energy method. The four stages are plug formation, dishing formation, petal formation and projectile exit. In addition, some important experimental results are presented and analyzed to validate the present perforation model. In the experiments, high speed camera system is used to record the perforation process. Observations on target damage and measurements of initial velocities and residual velocities with the aid of the system are presented. Numerical simulations are carried out for projectiles against single and layered plates adopted in the experiments. The perforation process is studied and the deformation and failure modes are obtained. The predictions of numerical simulations and analytical model are found in reasonably good agreement with those of experiments, and can be used to predict the ballistic limit and residual velocity of stiffened plates perforated by rigid projectiles.

关键词： perforation Penetration Impact Stiffened plate Numerical simulations Failure modes

Impact of hydraulic perforation on fracture initiation and propagation in shale rocks

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Science China(Technological Sciences) 2016年第5期59卷 756-762页

作者： ZHAO Xi JU Yang YANG Yong SU Sun GONG WenBo School of Mechanics & Civil Engineering China University of Mining & Technology Beijing 100083 China State Key Laboratory for Geo-mechanics & Deep Underground Engineering China University of Mining & Technology Xuzhou 221006 China State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Beijing 100083 China SINOPEC Shengli Oilfield Company Geological Scientific Research Institute Dongying 257015 China

To enhance the oil and gas recovery rate, hydraulic fracturing techniques have been widely adopted for stimulation of low-permeability reservoirs. Pioneering work indicates that hydraulic perforation and layout could significantly affect fracture initiation and propagation in low-permeability reservoir rocks subjected to complex in-situ stresses. This paper reports on a novel numerical method that incorporates fracture mechanics principles and the numerical tools FRANC3D and ANSYS to investigate the three-dimensional initiation and propagation behavior of hydro-fracturing cracks in shale rock. Considering the transverse isotropic property of shale rocks, the mechanical parameters of reservoir rocks attained from laboratory tests were adopted in the simulation. The influence of perforation layouts on the 3D initiation of hydro-fracturing fractures in reservoir rocks under geo-stresses was quantitatively illuminated. The propagation and growth of fractures in three dimensions in different perforating azimuth values were illustrated. The results indicate that： 1） the optimal perforation direction should be parallel to the maximum horizontal principal stress, 2） the crack plane gradually turns toward the direction of the maximum horizontal principal stress when they are not in parallel, 3） compared with the linear and symmetric pattern, the staggered perforation is the optimal one, 4） the proper perforation density is four to six holes per meter, 5） the optimal perforation diameter in this model is 30 ram, and 6） the influence of the perforation depth on the fracture initiation pressure is low.

关键词： hydraulic fracturing perforation shale rocks in-situ stresses numerical simulation fracture mechanics

A three-stage model for the perforation of finite metallic plates by long rods at high velocities

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Defence Technology（防务技术） 2019年第3期15卷 409-418页

作者： Yu He Liu-yun Xu He-ming Wen Zheng-cao Lu National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics CAEP Mianyang 621900 China CAS Key Laboratory for Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei Anhui 230027 China

A three-stage theoretical model is presented herein to predict the perforation of a thick metallic plate struck normally by a long rod at high velocities. The model is suggested on the basis of the assumption that the perforation of a thick metallic plate by a long rod can be divided into three stages:(1) initial penetration;(2) plug formation and (3) plug slipping and separation. Various analytical equations are derived which can be employed to predict the ballistic limit, residual velocity and residual length of the long rod. It is demonstrated that the present model predictions are in good agreement with available experimental results for the perforation of finite steel targets struck normally by steel as well as tungsten alloy long rods at high velocities. It is also demonstrated that the dynamic maximum shear stress of a plate material has strong effect on plug formation and plug thickness which, in turn, exerts considerable influence on the residual velocities and lengths of a long rod at impact velocities just above the ballistic limit.

关键词： perforation Long rod Finite metallic plate Ballistic limit Residual velocity Residual length