Bending Failure Mode and Prediction Method of the Compressive Strain Capacity of A Submarine Pipeline with Dent Defects

A dent is a common type of defects for submarine pipeline.For submarine pipelines,high hydrostatic pressure and internal pressure are the main loads.Once pipelines bend due to complex subsea conditions,the compression strain capacity may be exceeded.Research into the local buckling failure and accurate prediction of the compressive strain capacity are important.A finite element model of a pipeline with a dent is established.Local buckling failure under a bending moment is investigated,and the compressive strain capacity is calculated.The effects of different parameters on pipeline local buckling are analyzed.The results show that the dent depth,external pressure and internal pressure lead to different local buckling failure modes of the pipeline.A higher internal pressure indicates a larger compressive strain capacity,and the opposite is true for external pressure.When the ratio of external pressure to collapse pressure of intact pipeline is greater than 0.1,the deeper the dent,the greater the compressive strain capacity of the pipeline.And as the ratio is less than 0.1,the opposite is true.On the basis of these results,a regression equation for predicting the compressive strain capacity of a dented submarine pipeline is proposed,which can be referred to during the integrity assessment of a submarine pipeline.

Finite element analysis of stiffness and static dent resistance of aluminum alloy double-curved panel in viscous pressure forming

The static dent resistance performance of the aluminum alloy double-curved panel formed using viscous pressure forming (VPF)was studied by finite element analysis,which mainly considers the forming process conditions.The whole simulation consisting of three stages,i.e.,forming,spring-back and static dent resistance,was carried out continuously using the finite element code ANSYS.The influence of blank holder pressure(BHP)and the drawbead on the stiffness and the static dent resistance of the panels formed using VPF was analyzed.The results show that the adequate setting of the drawbead can increase the plastic deformation of the double-curved panel,which is beneficial to the initial stiffness and the static dent resistance.There is an optimum BHP range for the stiffness and the static dent resistance.

THREE KINDS OF DENTABILITIES IN BANACH SPACES AND THEIR APPLICATIONS

In this paper,we study some dentabilities in Banach spaces which are closely related to the famous Radon-Nikodym property.We introduce the concepts of the weak^(*)-weak denting point and the weak^(*)-weak^(*)denting point of a set.These are the generalizations of the weak^(*)denting point of a set in a dual Banach space.By use of the weak^(*)-weak denting point,we characterize the very smooth space,the point of weak^(*)-weak continuity,and the extreme point of a unit ball in a dual Banach space.Meanwhile,we also characterize an approximatively weak compact Chebyshev set in dual Banach spaces.Moreover,we define the nearly weak dentability in Banach spaces,which is a generalization of near dentability.We prove the necessary and sufficient conditions of the reflexivity by nearly weak dentability.We also obtain that nearly weak dentability is equivalent to both the approximatively weak compactness of Banach spaces and the w-strong proximinality of every closed convex subset of Banach spaces.

Effects of Controlled-Release Fertilizers and Their Application Methods on Germination and Seedling Growth of Dent and Sweet Corns

Effects of controlled-release fertilizers (CRFs) (C-AS, polyolefin coated ammonium sulfate, 50-day-type; Dd-LP, polyolefincoated urea with dicyandiamide, 40-day-type; C-ANP, polyolefin coated ammonium nitrate phosphate, 40-day-type; andC-DAP, polyolefin coated diammonium acid phosphate, 40-day-type), ammonium sulphate and no fertilizer control, andtheir application methods (spot, band, surface and mixed) on germination and seedling development of sweet corn (Zeamays L.var. saccharata Sturt.) and dent corn (Zea mays L.var. indentata Sturt.) were investigated in a greenhouse. Underco-situs application (band and spot) of CRFs, there were no obvious differences in the germination speed and rate for bothdent corn and sweet corn relative to control. Mortality rates of sweet corn seedlings under co-situs application were highin experiment 1, but were very low in experiment 2, because the environmental conditions were different in the twoexperiments. That is, under lower temperature and weaker sunlight, young seedlings easily die due to high soil nutrientconcentration and slow growth speed of corn. Shoot weight of both dent and sweet corn did not greatly decrease inexperiment 1. In experiment 2, there were no significant differences in shoot and root weight of both corns between co-situs and surface or mixed application methods. However, with spot and band application of ammonium sulfate, shoot androot weight were significantly reduced. Soil EC and pH were considerably affected by co-situs application, especially atthe fertilizer application site. For both dent and sweet corn, EC in the 0-3 cm soil was significantly higher under co-situsapplication and surface application than that under mixed application, whereas in the 3-6 cm soil depth the situation wasreversed. Compared with control, mixed application of CRFs decreased soil pH slightly (0-3 cm depth) or greatly (3-6 cmdepth).

Influence of dent on residual ultimate strength of 2024-T3 aluminum alloy plate under axial compression

Drop-weight impact tests were conducted on 2024-T3 aluminum plates with five types of impactors, and then the effects of the dent on the residual ultimate strength of the 2024-T3 specimens were investigated through axial compression tests. Results indicate that with increase in dent depth, the five types of dents affect the ultimate strength of the plate in different trends. Nevertheless, other than the plate global deflection caused by impacting, the dent itself has unremarkable effect on the ultimate strength. The mathematical expressions are derived regarding the relationship between impact energy factor and the dent depth factor as well as the compressive ultimate strength reduction rate and the dent depth factor.

以范可尼综合征和早发肾功能异常起病的Dent病1家系报道并文献复习

Dent病(Dent disease)是一种罕见的X连锁隐性遗传性的近端肾小管疾病,因CLCN5基因(Dent病1型)和OCRL基因(Dent病2型)突变所致[1-2],临床主要特征为小分子蛋白尿(low-molecular weight proteinuria,LMWP)、高钙尿症(hypercalciuria)和肾钙质沉着症(nephrocalcinosis),随病程进展部分患者可出现肾功能异常或肾衰竭[3-5]。此外,Dent病临床还可以有其他多种表现,包括泛氨基酸尿、磷酸盐尿、糖尿症、血尿、尿酸化功能障碍、佝偻病或骨软化症等[6-7]。

表现为大量蛋白尿的儿童Dent病一例

本文报道1例表现为大量蛋白尿的Dent病患儿诊疗过程。患儿男性,3岁1个月,常规体检时发现有大量蛋白尿,无低白蛋白血症,尿蛋白电泳提示以小分子量蛋白为主,同时伴高钙尿症,有阴离子间隙正常的代谢性酸中毒,无糖尿,无氨基酸尿,肾脏超声未见肾脏钙质沉着。患儿无生长发育落后及肾脏疾病家族史。完善全外显子组基因检测到OCRL1基因第15号外显子存在1处错义变异c.1477C>T(p.Arg493Trp)。诊断Dent病明确后,限制高钙、高钠及高草酸盐饮食摄入,同时加用枸橼酸钾颗粒及氢氯噻嗪口服。目前随访2个月,尿钙水平下降,肾功能稳定。本文通过典型病例报道及既往文献回顾,以期提高临床医师对该疾病的认识,并为该疾病的诊治提供借鉴。

Effect of mechanical threshing on damage and vigor of maize seed threshed at different moisture contents

Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality.The purpose of this study was to assess the effect of mechanical threshing on the quality of maize seed threshed at different moisture contents(MCs).Seeds of dent maize JK968 and flint maize DD2 were threshed at 12,15,18,21,and 24% MC.The damage degree was determined by iodine staining,and seed vigor was assessed by standard germination(SG),cold test germination(CTG),accelerated aging germination(AAG),seedling emergence rate,and seedling root and shoot length.The results showed that the damage percentage increased,and the seed vigor parameters decreased with increasing seed MC during threshing in both cultivars.For obtaining high seed quality,indicated by at least 90,85,and 80% of SG,AAG,and CTG,respectively,JK 968 and DD2 should be threshed at MC lower than 15 and 18%,respectively.Furthermore,the damage mainly occurred in the apical part of seeds,irrespective of the threshing MC in both cultivars.When the embryo was damaged,seedling emergence rates were significantly reduced with great influence on shoot length.Damage to the endosperm resulted in little effect on seedling performance.Flint maize DD2 was more tolerant to mechanical threshing than dent maize JK968.These results provided technical reference for the production and processing of high vigor maize seeds.

Preliminary Study on Evaluation System of Capability of Composites to Withstand Impact

This paper summarizes the authors’ experimental study on the characterization system of composite behavior to withstand impact. The content includes: (1)The dent depth is the best parameter describing the impact damage state. (2) There exists the knee point phenomenon for damage resistance behavior (i.e. the relationship between impact energy or contact force and dent depth) and damage tolerance behavior (i.e. the relationship between dent depth and compressive failure strain or stress) of composite laminates. (3) The physical meaning of the knee point phenomenon is that the failure mechanisms change of damaged composites to fiber breakage in the first front plies from matrix crack and delamination. Some suggestions on the characterization system of composite behavior to withstand impact were proposed.

Standards and methods for dent assessment and failure prediction of pipelines:A critical review

Dent,a common mechanical damage on pipelines,is associated with a significant local plastic deformation.Dents can cause pipeline failures,especially when they are combined with other types of defects such as gouges,fatigue,corrosion,and cracks.In this work,a systematic review of various assessment methods and standards for pipeline dents,including the combination of a dent with other defects,is conducted.Generally,the methods available today are not sufficiently accurate and reliable to assess pipeline dents,especially the dent-defect combinations.For plain dents on pipelines,both the depthbased criterion and the strain-based criterion are commonly used in engineering.Their main problems include inaccuracy and conservatism.For a dent combined with other defects,the existing assessment techniques are not mature enough to give reliable results.Both experimental testing and numerical modeling through finite element(FE)analysis are capable of investigating the influence of dents and dent-defect combinations on burst failure pressure of the pipelines,although an approximation to the reality is still the main difficulty existing in the experimental testing and FE analysis.Nowadays,relevant studies on assessment techniques for plain dents,a dent with fatigue and a dent with a single gouge have been common in literature.The combinations of a dent with corrosion or cracks have been rarely assessed due to complicated mechanisms involving a multi-physics coupling effect.Development of novel assessment methods by integrating mechanical stress and strain,electrochemical reactions and steel metallurgy will be a key topic to accurately assess the dent-defect combinations for improved pipeline integrity.

Cooperative Channel and Optimized Route Selection in Adhoc Network

Over the last decade,mobile Adhoc networks have expanded dramati-cally in popularity,and their impact on the communication sector on a variety of levels is enormous.Its uses have expanded in lockstep with its growth.Due to its instability in usage and the fact that numerous nodes communicate data concur-rently,adequate channel and forwarder selection is essential.In this proposed design for a Cognitive Radio Cognitive Network(CRCN),we gain the confidence of each forwarding node by contacting one-hop and second level nodes,obtaining reports from them,and selecting the forwarder appropriately with the use of an optimization technique.At that point,we concentrate our efforts on their channel,selection,and lastly,the transmission of data packets via the designated forwarder.The simulation work is validated in this section using the MATLAB program.Additionally,steps show how the node acts as a confident forwarder and shares the channel in a compatible method to communicate,allowing for more packet bits to be transmitted by conveniently picking the channel between them.We cal-culate the confidence of the node at the start of the network by combining the reliability report for thefirst hop and the reliability report for the secondary hop.We then refer to the same node as the confident node in order to operate as a forwarder.As a result,we witness an increase in the leftover energy in the output.The percentage of data packets delivered has also increased.

Wear Resistance and Indentation Behavior of Equiatomic Superelastic TiNi and 60NiTi

Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.

Functional coupling of V-ATPase and CLC-5

Dent’s disease is an X-linked renal tubulopathy characterized by low molecular weight proteinuria, hypercalciuria and progressive renal failure. Disease aetiology is associated with mutations in the CLCN5 gene coding for the electrogenic 2Cl-/H＋ antiporter chloride channel 5 （CLC-5）, which is expressed in the apical endosomes of renal proximal tubules with the vacuolar type H＋-ATPase （V-ATPase）. Initially identified as a member of the CLC family of Cl- channels, CLC-5 was presumed to provide Cl shunt into the endosomal lumen to dissipate H＋ accumulation by V-ATPase, thereby facilitating efficient endosomal acidification. However, recent findings showing that CLC-5 is in fact not a Cl- channel but a 2Cl-/H＋ antiporter challenged this classical shunt model, leading to a renewed and intense debate on its physiological roles. Cl- accumulation via CLC-5 is predicted to play a critical role in endocytosis, as illustrated in mice carrying an artifcial Cl- channel mutation E211A that developed defective endocytosis but normal endo-somal acidification. Conversely, a recent functional analysis of a newly identifed disease-causing Cl- channel mutation E211Q in a patient with typical Dent’s disease confrmed the functional coupling between V-ATPase and CLC-5 in endosomal acidifcation, lending support to the classical shunt model. In this editorial, we will address the current recognition of the physiological role of CLC-5 with a specific focus on the functional coupling of V-ATPase and CLC-5.

Experiments and computer simulation analysis of impact behaviors of micro-sized abrasive in waterjet cutting of thin multiple layered materials

The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development efforts have recently been made to understand the science of AWJ.However,the interaction mechanism between a workpiece and high-velocity abrasive particles still remains a complicated problem.In this work,the material removal mechanisms of AWJ such as micro penetration and micro dent were experimentally investigated.In addition,a new computer simulation model considering high strain rate effect was proposed to understand the micro impact behavior of high-velocity micro-sized abrasives in AWJ cutting.

A NEW MODEL FOR CALCULATING PROPAGATION PRESSURE AND INITIATION PRESSURE OF PIPELINES WITH A LOCAL DENT

An analytical model of a ring with six yield hinges and two deformable arc segments is presented for. the prediction of the buckle propagation pressure and initiation pressure in offshore pipelines. The configuration of a fully collapsed ring is considered as a real dumbbell shape with a line touch between two 'bells', instead of the dumbbell shape with a point touch of two diametrically opposite points. Calculations are performed assuming that the dominant effect on the plastic energy dissipation has the circumferential bending mode. For the linear strain-hardening materials it is found that theoretical predictions based on the above model for both propagation pressure and initiation nressure are in good agreement with experimental results of Kyriakides et al.

1例儿童1型Dent病伴Bartter综合征病例分析并文献复习

目的:分析1例1型Dent病伴Bartter综合征样患儿的临床症状及诊疗过程,以提高临床对该疾病的认识。方法:采用回顾性分析方法,收集我院经临床特征和基因检测确诊的1例1型Dent病伴Bartter综合征患儿的临床资料,分析其临床特征及诊疗过程并复习文献。结果:本例患儿以Bartter综合征样表现(顽固性低钾血症,血浆肾素、醛固酮水平升高,血压正常)为初始表现,并有尿蛋白定量明显升高,以低分子量蛋白(LMWP)尿为主,α1、β2微球蛋白(MG)水平明显升高,基因分析提示CLCN5基因c.1265-c.1266 insA(半合子突变)。但本例患儿初始肾功能正常,泌尿系统超声检查结果未见异常。初期采用饮食调控(如低草酸盐、低钠、低钙等),口服补钾及盐酸贝那普利0.25 mg/(kg·d)治疗1个月后,发生急性肾损伤,给予甲泼尼龙及血液净化治疗后肾功能好转。结论:Dent病临床表型复杂,需及时完善基因检测协助诊断,具有Bartter综合征临床症状的Dent病患者易发展为肾功能衰竭,应及时评估肾功能及长期规律随访。

Dent病6例临床诊治分析

目的 探讨Dent 病的诊断及治疗.方法 回顾性分析2014 年1 月至2015 年8 月收治的曾被外院误诊为肾病综合征的6 例Dent 病患儿的临床特点、诊治过程以及相关致病基因突变分析.结果 6例患儿均为男性,年龄4.5 - 9.8 岁,临床主要表现为达肾病水平的蛋白尿,有-过性低白蛋白血症（26 - 30 g/L）,均无明显水肿、高胆固醇血症.其中4 例患儿行肾活检,2 例为轻度系膜增生性肾小球肾炎、2 例为局灶节段性肾小球硬化.6 例患儿在对足量激素耐药后均联用至少一种或多种免疫抑制剂,蛋白尿均未见明显变化.入院后检查示低分子蛋白尿,肾早期损伤指标α1 微球蛋白（α1-MG）与微量白蛋白（MA）的比值均〉 1,伴高钙尿症、不伴肾功能异常,其中2 例B超可见肾脏钙化影像,符合Dent 病临床诊断.进一步的基因分析证实6 例患儿均存在CLCN5 基因致病突变.结论 作为一种罕见的遗传性肾小管疾病,Dent 病在临床上易被误诊误治,应引起临床儿科医师的重视.肾早期损伤指标α1-MG/MA 〉 1,可作为肾小管性蛋白尿的诊断标准之一.

Dent病合并肾衰竭2例报告并文献复习

目的探讨儿童Dent病合并肾衰竭的病因及预后。方法分析2014年1月至2016年12月收治的2例Dent病合并肾衰竭患儿的临床资料,并结合文献进行复习。结果 2例患儿均为男性,年龄分别为8、10岁;既往肾功能均正常,无肾脏钙化;肾衰竭发病前1周内均有上呼吸道病毒感染史。例1疾病急性期(10天)肾活检提示合并急性小管间质性肾炎,经激素治疗后肾功能完全恢复;例2病程6个月时肾活检提示合并亚急性小管间质性肾炎,经激素治疗后肾功能稍有改善但未恢复正常。结论对于Dent病患儿发生急性肾衰竭,特别是有上呼吸道病毒感染等诱因者,应及早行肾活检,以除外合并急性间质性肾炎的可能,从而及时治疗、改善预后。

儿童2型Dent病1例并文献复习

目的总结1例2型Dent病患儿临床资料,提高对该病的认识。方法报道1例2型Dent病患儿的临床发现、相关实验室检查指标和肾活检病理改变。对该家系相关成员行CLCN5和OCRL基因外显子及附近调控区域直接测序,分析突变位点,并文献复习。结果患儿,男,6岁起病,首发症状为单纯性蛋白尿,未见先天性白内障、智力低下、认知障碍及发育迟缓。实验室检查提示低分子蛋白尿,高钙尿症,镜下血尿,血清乳酸脱氢酶和磷酸肌酸激酶增高,肾活检病理提示轻微病变。患儿CLCN5和OCRL基因测序分析发现,CLCN5基因未见致病性突变,ORCL基因c.260del A(p.Q87fs105X)纯合突变,确诊为2型Dent病。家系OCRL基因突变分析显示,患儿父亲c.260del A未检出突变,母亲携带c.260del A杂合突变。c.260del A突变为移码突变,可导致OCRL基因编码蛋白截短。结论 2型Dent病以低分子蛋白尿、高钙尿症和镜下血尿为特征,血清乳酸脱氢酶、磷酸肌酸激酶增高和OCRL基因纯合移码突变支持2型Dent病诊断。

合并肾囊性病变儿童1型Dent病1例报告

目的探讨儿童Dent病1型合并肾囊性病变的可能发病原因。方法回顾1例16岁男性肾囊性病变患儿的临床资料,并复习相关文献。结果患儿发现蛋白尿、双肾多发囊肿4年,肾功能异常3年,临床主要表现为肾病水平的小分子蛋白尿、高钙尿症、肾功能异常并进行性加重、双肾多发囊肿、低钾血症。肾脏病理为局灶节段性肾小球硬化伴肾小管间质损伤。CLCN 5基因突变分析示c. 1975 delC(p.R 659 Gfs*7),NPHP相关基因未见突变。诊断为Dent病1型合并肾囊性病变、慢性肾脏病。结论 Dent病1型合并肾囊性病变较为罕见,其确切机制尚不清楚。