Risk Based Optimal Inspection and Repair Planning for Ship Structures Subjected to Corrosion Deterioration

A framework of risk based inspection and repair planning was presented to optimize for the ship structures subjected to corrosion deterioration. The planning problem was formulated as an optimization problem where the expected lifetime costs were minimized with a constraint on the minimum acceptable reliability index. The safety margins were established for the inspection events, the repair events and the failure events for ship structures. Moreover, the formulae were derived to calculate failure probabilities and repair probabilities. Based on them, a component subjected to corrosion is investigated for illustration of the process of selecting the optimal inspection and repair strategy. Furthermore, some sensitivity studies were provided. The results show that the optimal inspection instants should take place before the reliability index reaches the minimum acceptable reliability index. The optimal target failure probability is 10 -3 . In addition, a balance can be achieved between the risk cost and total expected inspection and repair costs by means of the risk-based optimal inspection and repair method, which is very effective in selecting the optimal inspection and repair strategy.

Cost-Benefit Assessment of Inspection and Repair Planning for Ship Structures Considering Corrosion Model Uncertainty

Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective inspection. This paper aims to propose a cost-benefit assessment model of risk-based inspection and repair planning for ship structures subjected to corrosion deterioration. Then, the benefit-cost ratio is taken to be an index for the selection of the optimal inspection and repair strategy. The planning problem is formulated as an optimization problem where the benefit-cost ratio for the expected lifetime is maximized with a constraint on the minimum acceptalbe reliability index. To account for the effect of corrosion model uncertainty on the cost-benefit assessment, two corrosion models, namgly, Paik＇ s model and Guedes Soares＇ model, are adopted for analysis. A numerical example is presented to illustrate the proposed method. Sensitivity studies are also providet. The results indicate that the proposed method of risk-based cost-benefit analysis can effectively integrate the economy with reliability of the inspection and repair planning. A balance can be achieved between the risk cost and total expected inspection and repair costs with the proposed method, which is very. effective in selecting the optimal inspection and repair strategy. It is pointed out that the corrosion model uncertainty and parametric uncertaintg have a significant impact on the cost-benefit assessment of inspection and repair planning.

Oil/Gas Pipeline Leak Inspection and Repair in Underwater Poor Visibility Conditions: Challenges and Perspectives

Mechanical pressure clamps are examples of innovative tools commonly used in the oil and gas industry for arresting leaks from damaged oil and gas pipelines. However, if leaks result from pipeline rupture, clamps are not usually recommended. It is therefore obvious that inspection of the leaking pipeline is very crucial in deciding the strategy for repair. For subsea pipelines where underwater poor visibility is pronounced, this important aspect of the pipeline repair process becomes difficult to implement. The result is a repair-leak-repair cycle. This challenge is commonly found in repairs of old pipelines in unclear water conditions. Old pipelines and their vulnerability to fractures that often lead to ruptures are discussed. In this paper, the challenges and technologies available for visualisation and examination in such unclear water conditions are discussed. There appears to be a gap in the existing pipeline integrity management system with respect to inspection and repair of pipelines in unclear water conditions. This gap needs to be filled in order to minimise spills and pollution. For pipelines installed in unclear water condition, a perspective is suggested to extend the capability of existing remotely operated vehicles to employ the use of clear laminar water system or a related technique to provide integrity engineers and operators with close visual assess to inspect leaking pipelines and effect adequate repairs. This paper suggests that the use of optical eye as the main tool for examination remains valuable in managing the challenges in underwater pipeline repairs in unclear water condition.

Research on Operation Safety of Urban Rail Transit Based on Automatic Ticket Checking(AFC)System

At present,after the actual inspection of the rail transit automatic ticket checking system,some security vulnerabilities have appeared,and there are also some defects in information security.For example,the database and virus protection need to be analyzed and upgraded in order to cope with the increasing number of information security risks.This article analyzes the security problems in the AFC system,and puts forward related suggestions and solutions,hoping to provide some reference for technical developers.

PROBABILITY OF RANDOM EVENTS OF INSPECTION AND REPAIR AND MAINTAINING RELIABILITY OF STRUCTURES

Reliability analysis of the inspected and repaired structure requires dealing with a large number of complex random events. Considering many kinds of random factors, a probability of these random events existing possibly in the inspection and repair process and reliability analysis methodologies are proposed. A systematic dynamic reliability model is given for structures in service under the scheduled inspection and repair.

Systematic review and meta-analysis of outcomes of anatomic repair in congenitally corrected transposition of great arteries

BACKGROUND Treatment of congenitally corrected transposition of great arteries(cc-TGA)with anatomic repair strategy has been considered superior due to restoration of the morphologic left ventricle in the systemic circulation.However,data on long term outcomes are limited to single center reports and include small sample sizes.AIM To perform a systematic review and meta-analysis for observational studies reporting outcomes on anatomic repair for cc-TGA.METHODS MEDLINE and Scopus databases were queried using predefined criteria for reports published till December 31,2017.Studies reporting anatomic repair of minimum 5 cc-TGA patients with at least a 2 year follow up were included.Metaanalysis was performed using Comprehensive meta-analysis v3.0 software.RESULTS Eight hundred and ninety-five patients underwent anatomic repair with a pooled follow-up of 5457.2 patient-years(PY).Pooled estimate for operative mortality was 8.3%[95%confidence interval(CI):6.0%-11.4%].0.2%(CI:0.1%-0.4%)patients required mechanical circulatory support postoperatively and 1.7%(CI:1.1%-2.4%)developed post-operative atrioventricular block requiring a pacemaker.Patients surviving initial surgery had a transplant free survival of 92.5%(CI:89.5%-95.4%)per 100 PY and a low rate of need for pacemaker(0.3/100 PY;CI:0.1-0.4).84.7%patients(CI:79.6%-89.9%)were found to be in New York Heart Association(NYHA)functional class I or II after 100 PY follow up.Total re-intervention rate was 5.3 per 100 PY(CI:3.8-6.8).CONCLUSION Operative mortality with anatomic repair strategy for cc-TGA is high.Despite that,transplant free survival after anatomic repair for cc-TGA patients is highly favorable.Majority of patients maintain NYHA I/II functional class.However,monitoring for burden of re-interventions specific for operation type is very essential.

Minimum dose path planning for facility inspection based on the discrete Rao-combined ABC algorithm in radioactive environments with obstacles

Workers who conduct regular facility inspections in radioactive environments will inevitably be affected by radiation.Therefore,it is important to optimize the inspection path to ensure that workers are exposed to the least amount of radiation.This study proposes a discrete Rao-combined artificial bee colony(ABC)algorithm for planning inspection paths with minimum exposure doses in radioactive environments with obstacles.In this algorithm,retaining the framework of the traditional ABC algorithm,we applied the directional solution update rules of Rao algorithms at the employed bee stage and onlooker bee stage to increase the exploitation ability of the algorithm and implement discretion using the swap operator and swap sequence.To increase the randomness of solution generation,the chaos algorithm was used at the initialization stage.The K-opt operation technique was introduced at the scout bee stage to increase the exploration ability of the algorithm.For path planning in an environment with complex structural obstacles,an obstacle detour technique using a recursive algorithm was applied.To evaluate the performance of the proposed algorithm,we performed experimental simulations in three hypothetical environments and compared the results with those of improved particle swarm optimization,chaos particle swarm optimization,improved ant colony optimization,and discrete Rao’s algorithms.The experimental results show the high performance of the proposed discrete Rao-combined ABC algorithm and its obstacle detour capability.

Reliability Analysis of a Cold Standby Repairable System with Repairman Extra Work

This paper deals with a cold standby repairman who can do extra work in idle time. The repairable system with two identical units and one authors are devoted to studying the unique existence and exponential stability of the system solution. C0-semigroup theory is used to prove the existence of a unique nonnegative time-dependent solution of the system. Then by using the theory of resolvent positive operator, the authors derive that dynamic solution of the system exponentially converges to its steady-state one which is the eigenfunction corresponding to eigenvalue 0 of the system operator. Some reliability indices of the system are discussed with a different method from traditional one. The authors also make a profit analysis to determine the optimal service time outside the system to maximize the system profit.

Utility of single-incision totally extraperitoneal inguinal hernia repair with intraperitoneal inspection

AIM To study the utility of single-incision totally extraperitoneal inguinal hernia repair with intraperitoneal inspection.METHODS A 2 cm transverse skin incision was made in the umbilicus, extending to the intraperitoneal cavity. Carbon dioxide was insufflated followed by insertion of laparoscope to observe the intraperitoneal cavity. The type of hernia was diagnosed and whether there was the presence of intestinal incarceration was confirmed. When an intestinal incarceration in the hernia sac was found, the forceps were inserted through the incision site and the intestine was returned to the intraperitoneal cavity without increasing the number of trocars. Once the peritoneum was closed, totally extraperitoneal inguinal hernia repair was performed, and finally, intraperitoneal observation was performed to reconfirm the repair.RESULTS Of the 75 hernias treated, 58 were on one side, 17 were on both sides, and 10 were recurrences. The respective median operation times for these 3 groups of patients were 100 min(range, 66 to 168), 136 min(range, 114 to 165), and 125 min(range, 108 to 156), with median bleeding amounts of 5 g(range, 1 to 26), 3 g(range, 1 to 52), and 5 g(range, 1 to 26), respectively. Intraperitoneal observation showed hernia on the opposite side in 2 cases, intestinal incarceration in 3 cases, omental adhesion into the hernia sac in 2 cases, severe postoperative intraperitoneal adhesions in 2 cases, and bladder protrusion in 1 case. There was only 1 case of recurrence.CONCLUSION Single-incision totally extraperitoneal inguinal hernia repair with intraperitoneal inspection makes hernia repairs safer and reducing postoperative complications. The technique also has excellent cosmetic outcomes.

Early mobilization program and rehabilitation after flexor tendon repair

Objective To investigate the methods and significance of early mobilization to the function rehabilitation after flexor tendon repair.Methods 286 complete flexor tendon amputation in 116 cases which was not combined with fractures were repaired.From the third day after operation,the digits were mobilized with a combination of assisted passive flexion and active extension simultaneously in the first 4 weeks.The digits flexing and extending scope was increased gradually controlled by doctors.Unassisted active flexion extension exercises begun 4 weeks after operation.The injured fingers were given physical therapy of voice band therapy 4 weeks postoperatively,ultrashort wave treatment 4 weeks and wax hot therapy 6 week postoperatively.Patients were followed up once weekly to be instructed how to go on functional training after they were discharged.Results Patients were followed up from 6 to 18 months.The function recovery of the corresponding fingers was evaluated by TAM method which included 192 excellent digits(77.1%),25 fine digits(10.0%),15 normal digits(6.0%) and 17 bad digits (6.8%).Conclusion It was inevitable for the repaired tendon to be adhered to the around tissue.Early mobilization of relevant injured fingers could enhance formation of non limited adhesion,increase excursion of the reconditioned tendon and revert tendon intensity at early time.Early mobilization should begin at 3 days after operation.

Study of Optimal Frequency to the Repairable System Due to Failure Finding Interval to Maximize Availability System

This research article is based on a study of optimal frequency to the repairable system due to the failure finding interval to maximize as well as minimize the availability of some components devices. We studied together maintenance and corrective actions that carried out item of failure and periodic failure finding designed to check whether a system is still working. The model is proved as well as useful application in detecting the problem related to finding failure tasks of different scheme devices by maximization. The model formulated and the numerical application to the relevant mathematical model have been discussed to demonstrate the article quality. Therefore based on probability analytic development, the optimal maintenance policy is then obtained as solution of an optimization problem in which the maintenance cost rate is the objective function and the risk of corrective maintenance is the constraint function. Finally, the solution to the optimal device in the considered development model has been well adjusted due to derivation to the experimental observation rather than theory which will be taken into consideration in the next applied practical design research related and the system device provided that, the proactive device agreed with using the exponential distribution to the survive distribution function which can not be considered as valid.

活性改性剂合成及其对环氧胶黏剂力学与界面粘接性能的影响

综合考虑环氧胶黏剂的施工性能、力学性能及与砂浆界面的粘接性能,利用三羟甲基丙烷三缩水甘油醚(TMPGE)与1,4-丁二醇(BDO),通过控制反应物物质的量比以及反应时间制备了四种低环氧值兼具高羟基含量的预聚体(PPM)。通过1H-NMR、盐酸-丙酮法及凝胶渗透色谱(GPC)对PPM进行了表征。进一步研究了PPM对改性环氧胶黏剂工作性能、固化力学性能、与水泥砂浆粘接强度以及表面性质的影响。结果显示:延长反应时间以及增加BDO用量使PPM的数均分子量更大、环氧值更低。四种PPM改性后,胶黏剂的放热峰值温度降低,可操作时间延长。同时,PPM使环氧固化物的延性显著增加。四种PPM改性后使环氧与水的接触角降低,固化物表面的极性组分升高。XPS分析表明,PPM使环氧固化物的羟基含量显著提高。最后,PPM使胶黏剂对湿砂浆基体的粘接强度提高了一倍以上。

挂牌督办:中国式行政督查制度

为有效应对日趋复杂的安全治理形势,发轫于社会治安治理而后被推广至生态环保、安全生产等领域的挂牌督办制度,将中国特色的督查机制创造性融入复杂的治理场景之中,取得了显著的治理成效,成为近年来被频繁使用和研究的中国公共管理关键词。挂牌督办所蕴含的政治压力、社会压力和时间压力形成了强大的政治势能,促使地方政府及其职能部门等督办客体迅即强化其政治执行力、组织协同力和社会回应力,进而在较短的时间内完成中央政策目标、提升安全治理效能。同时,我们应秉持理性科学的态度客观评估挂牌督办的治理绩效,在厘清其效能边界的基础上,以更高质量的研究工作清晰识别其运行的底层逻辑,为确保挂牌督办制度始终发挥正向功能提供对策参考。

基于协同育人理念的产业学院建设实践——以钢铁智能制造产业学院为例

产业学院作为深化产教融合、校企合作的重要载体,有效实现了人才培养与产业需求的对接。武汉工程职业技术学院钢铁智能制造产业学院立足钢铁制造产业转型升级发展,以冶金设备智能运维省级高水平专业群为载体,通过创新“五接五融五双”人才培养模式,共同实施“五段递进式”教学,打造“双师型”教师团队,共建生产性实训基地,共同开发活页式教材,培养“操检维调”高素质技能人才。

煤化工装置法兰接头密封泄漏评估管理系统研发

煤化工装置中螺栓法兰接头的泄漏问题一直是安全和环保管理的关键挑战。为解决此问题,文中设计并开发了涵盖了数据收集管理、密封泄露检测及修复、LEC泄漏风险评估及统计分析等功能的评估管理系统。通过该系统,可以实时监测密封泄漏、进行数据分析评估,并采用LEC评价法进行风险评估。系统业务模块面向不同管理层级的需求,有助于提高煤化工装置法兰接头密封泄漏评估管理的科学性和效率。系统致力于提高装置的密封性能、降低泄漏风险、合理配置检维修资源,从而实现装置的长周期运行。

基于本体的几何误差检验操作构建与推理

针对新一代产品几何技术规范与认证(Geometrical Product Specification and Verification,GPS)标准在实际工程中的应用程度较低、各操作之间难以集成使用、过度依赖检验者经验的问题,开展几何误差检验操作的本体构建与推理研究。根据新GPS检验操作和零件测量信息,建立几何误差检验操作信息表示模型,基于信息表示模型来构建相应的几何误差检验操作本体,接着采用语义网规则语言(Semantic Web Rule Language,SWRL)建立检验操作智能推理的SWRL规则,以实例在Protegé中验证该方法的可行性。

带上盖开发地铁车辆基地运用检修库房净空高度设计

[目的]城市轨道交通车辆基地的上盖物业开发已成为上海、北京等诸多城市的车辆基地设计基本要求,为了有效解决上盖物业开发对盖下库房的影响,需对运用检修库房的净空高度进行研究。[方法]以车辆基地的运用库和联合车库作为研究对象,分析上盖开发车辆基地库房净空高度的主要影响因素,梳理运用检修库房净空高度设计流程;提出架空接触网制式和接触轨制式下的库房净空计算方法。[结果及结论]采用接触网制式时,需考虑接触网导线高度及安全距离、起重机走行轨轨顶标高及起重机高度、架空管线层高度、结构主梁高度等因素,停车列检库首层盖板的最小高度为7.5 m;检修库(除停车列检库、临修库外)首层盖板高度统一为8.5 m;临修库首层盖板的最小高度为13.5 m。采用接触轨制式时,影响因素除接触网导线高度外,其余均与接触网制式一致,停车列检库、周月检库房首层盖板高度分别为7.5 m和8.5 m。

汽车前挡风玻璃的精致修复技术

汽车前挡风玻璃精致修复隶属于汽车维修增值服务。文章在阐述汽车前挡风玻璃修复原理的基础上,识别汽车前挡风玻璃破损类型,分析破损类型修复的难易程度,研究破损允许的修复范围。同时针对汽车前挡风玻璃出现点状或缝状的微小损伤,运用玻璃破损修复工具,研究前挡风玻璃修复前处理阶段、修复阶段和后处理阶段的操作工艺,以达到外观和强度的双重改善。精致修复是一种先进的玻璃维修方式,用维修方式来代替传统的更换维修,为汽车前挡风玻璃的维修提供了一种新方式,降低了维修成本,减少了环境污染。此精致修复为车身修复人员维修汽车前挡风玻璃提供科学的指导。

基于内外场一体化的水面舰艇作战模型检验评估方法

针对水面舰艇作战模型检验验证与评估难题,研究作战模型检验评估需求和内容体系,提出基于内外场一体化的检验评估流程和方法,大样本多维度评价作战模型,提高模型的规范性和质量效能。

不同皮瓣修复术对口腔颌面部肿瘤术后缺损手术时间及口腔功能指标的影响

目的:分析口腔颌面部肿瘤术后缺损患者行不同皮瓣修复术治疗的效果。方法:选择口腔颌面部肿瘤术后缺损患者58例,随机分为对照组和观察组,各29例。两组均施以皮瓣修复手术治疗,对照组胸大肌位置选择皮瓣,观察组为股前外侧皮瓣,比较不同部位皮瓣的效果差异。结果:观察组并发症总发生率低于对照组;手术时间、拔除胃管时间、经口进食时间、皮瓣愈合时间短于对照组;皮瓣制作+显微吻合时间长于对照组;外形修复、正常进食、口腔开合功能、口腔容纳水测试、正常吞咽、咀嚼功能、语言表达能力、正常咬合功能分数,皮瓣成活率和修复满意度高于对照组(P<0.05)。结论:口腔颌面部肿瘤术后皮瓣修复患者行不同皮瓣修复术的效果存在差异,股前外侧皮瓣相对比胸大肌皮瓣更具备优势,可缩短手术时间,改善口腔功能,安全度、患者满意度较高。