Reflection and Transmission of Regular Waves from/Through Single and Double Perforated Thin Walls

In this paper, reflection and transmission coefficients of regular waves from/through perforated thin walls are investigated. Small scale laboratory tests have been performed in a wave flume firstly with single perforated thin Plexiglas plates of various porosities. The plate is placed perpendicular to the flume with the height from the flume bottom to the position above water surface. With this thin wall in the flume wave overtopping is prohibited and incident waves are able to transmit. The porosities of the walls are achieved by perforating the plates with circular holes. Model settings with double perforated walls parallel to each other forming so called chamber system, have been also examined. Several parameters have been used for correlating the laboratory tests’ results. Experimental data are also compared with results from the numerical model by applying the multi-domain boundary element method （MDBEM） with linear wave theory. Wave energy dissipation due to the perforations of the thin wall has been represented by a simple yet effective porosity parameter in the model. The numerical model with the MDBEM has been further validated against the previously published data.

The theoretical study on diagonal wave interaction with perforated-wall breakwater with rock fill

The interaction of diagonal waves with perforated-wall breakwater partially filled with rock fill is studied using the linear potential theory. By means of the matched eigenfunction expansion method, an analytical method is presented to calculate the reflection coefficient and the wave force coefficient of the breakwater. The calculated results of the reflection coefficient for limiting cases are the same to the existing results. The main effect factors of the reflection coefficient and the wave force coefficient are analyzed by numerical examples. With the increasing of thickness of rock fill, the wave force coefficient on the perforated wall generally decreases, while the reflection coefficient increases. With the increasing of the incident angle of the wave, the reflection coefficient of the breakwater first decreases, reaches its minimum, and then increases monotonously.

Surgical Outcomes Following Partial Breast Reconstruction with Chest Wall Perforator Flaps

Introduction: In the last two decades, chest wall perforator flaps (CWPF) have become a versatile tissue replacement technique for partial breast reconstruction following breast-conserving surgery (BCS) in well-selected cases. We present the surgical outcome of 81 patients with chest wall perforator flaps used for breast-conserving surgery. Methods: We recorded the outcomes of three oncoplastic breast surgeons who performed partial breast reconstruction with chest wall perforator flaps from 1st January 2018 to 30th June 2022 at Sherwood Forest Hospitals NHS Foundation Trust. Data were collected on patient demographics, including age, BMI, smoking status, bra size, previous treatments, type of CWPF procedure, tumor size (measured clinically, via imaging and histologically), biopsy results, specimen weight, margins involvement, re-operation rate, surgical site infection (SSI), flap loss, flap shrinkage, hematoma, and seroma rates. Results: A total of 81 patients were included in this study, with an average age of 55.7 years and a body mass index (BMI) of 26.7 kg/m2. The bra size varied between A to FF with A (7.4%), B (28.3%), C (38.2%), D (13.6%), DD (11.1%), and FF (1.2%). 14.8% of the patients had neoadjuvant chemotherapy (NACT). For 45 patients, LICAP (lateral intercostal artery perforator), 16 AICAP (anterior intercostal artery perforator), 13 MICAP (medial intercostal artery perforator), and for seven patients, LTAP (lateral thoracic artery perforator) flaps were used. The average tumor was measured at 15.75 mm clinically, 19.1 mm via imaging, and 19.6 mm histologically. Biopsy showed that 16% of the tumors were ductal carcinoma in situ (DCIS), and 84% were invasive. 16% of patients had involved margins, and re-excision was required in 10 patients, and completion mastectomy was performed in 2 patients. A thirty-day SSI rate was 6.2%, with flap-related complications, including flap loss and shrinkage, at 3.7% and 4.9%, respectively. In addition, 3.7% had a hematoma, and 17.3% had other complications. Conclusion: Partial breast reconstruction with perforator flaps is an excellent volume replacement technique in breast-conserving surgery with acceptable complications in well-selected cases.

Experimental Study of the Diffusion of a Confined Wall Jet through a Perforated Plate: Influence of the Porosity and the Geometry

This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positioned at distances of 10 cm and 20 cm below the jet inlet. The experiments were realized using 2D Laser Doppler Anemometer (LDA). Different profiles of mean and fluctuating velocities are presented. The presence of a perforated plate strongly modified the airflow pattern compared to an empty enclosure. The velocities above and below the plate depend on several parameters, including the porosity and the plate’s position relative to the inlet slot and the longitudinal position. The difference between the flow velocity above and below the plates could not be related using a universal formula that depends on these parameters. We also investigated the influence of a porous media of a height of 20 cm (a stack of spheres having a diameter of 3.75 cm) located below the perforated plate. The results highlight that the porous medium strengthens the effects of the perforated plate on the flow.

Experimental and Numerical Investigation of the Diffusion of a Confined Wall Jet through a Perforated Plate

When performing numerical modeling of fluid flows where a clear medium is adjacent to a porous medium, a degree of difficulty related to the condition at the interface between the two media, where slip velocity exists, is encountered. A similar situation can be found when a jet flow interacts with a perforated plate. The numerical modeling of a perforated plate by meshing in detail each hole is most often impossible in a practical case (many holes with different shapes). Therefore, perforated plates are often modeled as porous zones with a simplified hypothesis based on pressure losses related to the normal flow through the plate. Nevertheless, previous investigations of flow over permeable walls highlight the impossibility of deducing a universal analytical law governing the slip velocity coefficient since the latter depends on many parameters such as the Reynolds number, porosity, interface structure, design of perforations, and flow direction. This makes the modeling of such a configuration difficult. The present study proposes an original numerical interface law for a perforated plate. It is used to model the turbulent jet flow interacting with a perforated plate considered as a fictitious porous medium without a detailed description of the perforations. It considers the normal and tangential effects of the flow over the plate. Validation of the model is realized through comparison with experimental data.

ESOPHAGUS-STOMACH-ABDOMINAL WALL DRAINAGE FOR DELAYED INTRATHORACIC ESOHPAGEAL PERFORATION

Objective To design a technique of esophagus-stomach-abdominal wall drainage for the de-layed intrathoracic esophageal perforation and to improve the therapeutic results. Methods Four patients were treated by this simplified technique. There were 1 case of lower intrathoracic esophageal perforation to the left thorax , 1 high and 2 middle perforation to the right. This technique used two plastic tubes (chest tube) in a diameter about 1 .2cm . One tube served as an intercostal drainage tube to drain purulent effusion , the other was inserted abdominally through stomach to the esophagus about 10cm above the esophageal perforation. Results The four patients were treated successfully by the esophagus-stomach-abdominal wall drainage. There was no mortality or severe morbidity or complication. Hospitalizations were shortened. Conclusion This technique is simple, safe and effective. It may provide a more promising alternative method of treatment for delayed esophageal perforation, especially in the critically ill patients. The procedure can also be extended to deal with esophagus-stomach anastomotic leak.

粉煤地层绳索取心钻进孔壁坍塌分析及处理

在甘肃省景泰县郭家台煤炭资源详查ZK30-1孔施工中,因强行提“水钻”造成了长孔段孔壁严重坍塌事故。分析认为坍塌地层粉煤层位多、累计厚度大,围岩结构松散、破碎是造成孔壁坍塌的地质因素;冲洗液性能与地层岩性不适应是主要技术因素。通过引入低粘强抑制冲洗液,扫孔过程中轻压慢转、小泵量循环,成功处理了孔壁坍塌,顺利终孔。煤田钻探施工对冲洗液性能要求严格,用绳索取心钻探粉煤对冲洗液性能要求更为苛刻,在冲洗液配制和钻进过程中尤其需要加强对其性能变化的监控。

框界自然,叙事园庭——中国驻欧洲某馆改造工程中的建构技艺

以“框界自然,叙事园庭”为线索,通过对室外立面遮阳“景窗”和室内公共空间“景墙”的详细记述,呈现中国驻欧洲某馆改造过程中的设计思考和建构技艺。

杭州运河湾办公总部幕墙设计

杭州运河湾办公总部外立面设计新颖,幕墙体系复杂、构造精细。在此针对其设计的重难点进行分析,介绍了包括幕墙材料的选用、穿孔铝板与玻璃组合幕墙系统、全明框组合幕墙系统、穿孔铝板幕墙系统、精制直角钢龙骨玻璃幕墙系统的优化设计等。各系统设计在构造设计与安装工艺上较常规做法有明显改进和优化,通过系统结构静力分析、重要节点的有限元分析等,验证了设计的合理性和安全性。

Endoscopic transgastric drainage of a gastric wall abscess after endoscopic submucosal dissection

A 63-year-old woman was referred to our hospital for further examination because of an incidental finding of early gastric cancer.Endoscopic submucosal dissection(ESD)was successfully performed for complete resection of the tumor.On the first post-ESD day,the patient suddenly complained of abdominal pain after an episode of vomiting.Abdominal computed tomography(CT)showed delayed perforation after ESD.The patient was conservatively treated with an intravenous proton pump inhibitor and antibiotics.On the fifth post-ESD day,CT revealed a gastric wall abscess in the gastric body.Gastroscopy revealed a gastric fistula at the edge of the post-ESD ulcer,and pus was found flowing into the stomach.An intradrainage stent and an extradrainage nasocystic catheter were successfully inserted into the abscess for endoscopic transgastric drainage.After the procedure,the clinical symptoms and laboratory test results improved quickly.Two months later,a follow-up CT scan showed no collection of pus.Consequently,the intradrainage stent was removed.Although the gastric wall abscess recurred 2 wk after stent removal,it recovered soon after endoscopic transgastric drainage.Finally,after stent removal and oral antibiotic treatment for 1 mo,no recurrence of the gastric wall abscess was found.

Reconstruction of complex chest wall defects:A case report

BACKGROUND Chronic radiative chest wall ulcers are common in patients undergoing radiation therapy.If not treated early,then symptoms such as erosion,bleeding and infection will appear on the skin.In severe cases,ulcers invade the ribs and pleura,presenting a mortality risk.Small ulcers can be repaired with pedicle flaps.Because radioactive ulcers often invade the thorax,surgeons need to remove large areas of skin and muscle,and sometimes ribs.Repairing large chest wall defects are a challenge for surgeons.CASE SUMMARY A 74-year-old female patient was admitted to our department with chest wall skin ulceration after radiation therapy for left breast cancer.The patient was diagnosed with chronic radioactive ulceration.After multidisciplinary discussion,the authors performed expansive resection of the chest wall ulcers and repaired large chest wall defects using a deep inferior epigastric perforator(DIEP)flap combined with a high-density polyethylene(HDPE)patch.The patient was followed-up 6 mo after the operation.No pigmentation or edema was found in the flap.CONCLUSION DIEP flap plus HDPE patch is one of the better treatments for radiation-induced chest wall ulcers.

Numerical Analysis of the Structure of High-Strength Double-Layer Steel Plate Concrete Shaft by Drilling Method of Water-Bearing Weak Rock Formation

In order to ensure the safety of coal mine shaft construction, a double-layer steel plate concrete composite shaft wall structure was proposed. However, fewer studies were conducted on this structure, which made engineers too confused to fully recognize its feasibility of this structure. Hence, based on the previous experimental research on the Taohutu mine construction project in Ordos in Inner Mongolia, this research paper aims to provide a widely deep numerical analysis by the usage of the finite element software, in fact, to establish the corresponding numerical analysis model and make a comparison with the experimental data to get the rationality of the verified model. The influence of the composite characteristics of the steel plate and concrete on the ultimate bearing capacity and stress field of the shaft wall structure is studied here through the method of multi-factor analysis. Also, the optimal design scheme of the double-layer steel plate and concrete composite shaft wall structure is proposed in this research paper.

沉箱开孔形式对波浪反射的影响试验研究

为了降低码头前沿的波浪反射作用、改善船舶靠泊作业的泊稳条件,开孔沉箱越来越多地被应用在直立码头工程中,但相关行业规范尚缺少对沉箱开孔形式的系统性说明。以大连港大窑湾港区四期工程为例,通过物理模型试验,重点分析不同沉箱开孔形式对不规则波作用下码头前沿波高反射系数的影响。结果表明:短周期波浪通常比设计波浪情况下的反射系数要小;试验断面的消浪性能在设计低水位附近最为理想;沉箱胸墙设置消浪腔对减小断面波浪反射的效果不明显;波浪反射系数主要取决于开孔率。

玻璃-双曲面穿孔铝板复合幕墙施工技术

结合工程实例,通过对玻璃-穿孔铝板幕墙进行深化设计,并应用异形钢结构龙骨施工技术、双曲面穿孔铝板幕墙连接技术、大曲率模块化铝板拼装技术,解决了施工中存在的双曲面穿孔铝板优化、钢结构龙骨定位焊接、多角度龙骨连接以及大曲率、斜向分格穿孔铝板定位拼接等难题,最终实现了复合幕墙的快速建造,取得了良好的社会效益和经济效益,可为类似工程提供参考。

REFLECTION OF OBLIQUE INCIDENT WAVES BY PERFORATED CAISSONS WITH TRAVERSE WALL

The interaction of oblique incident waves with infinite number of perforated caissons is investigated. The fluid domain is divided into infinite sub-domains by the caissons, and eigen-function expansion is applied to expand velocity potentials in each domain. A phase relation is introduced for wave oscillation in each caisson, and the structure geometry is considered in constructing the models of reflection waves. The reflected waves with the present analysis include all of the waves traveling in different directions when incident wave period is short. Numerical examinations show that velocities at the inner and outer sides of the front walls of caissons ase close to each other, and reflection coefficients satisfy the energy conservation relation very well when porous effect parameter is infinite. Numerical results show that the reflection coefficients of oblique incident waves are smaller for shorter caissons at low frequency, and decrease with the increase of wave incident angle.

建筑地基冲孔灌注桩施工及承载力验算探讨

文中以建宁县人民武装部民兵训练基地项目为例,探究冲孔灌注桩冲孔、首次清孔、吊放钢筋笼、再次清孔和灌注混凝土等施工方法,并对桩身承载力进行验算,结果表明,本次冲孔灌注桩施工技术符合施工要求,达到了预期应用效果。

薄壁大通径膨胀管技术及其现场应用

随着以射孔段封堵、套管漏失修复、井筒腐蚀穿孔封堵为代表的老井井筒修复工作日益增多,传统膨胀管补贴技术所存在的作业效率低、补贴后有效通径小,以及补贴后常规完井工具难以下入、难以在补贴段以下进行二次补贴等一系列弊端日益凸显。为此,研发了一种薄壁大通径不锈钢膨胀管技术,并对该类膨胀管技术的相关装置结构、工作原理、施工工艺及配套技术进行了详细阐述。现场应用表明:①该类薄壁大通径不锈钢膨胀管补贴技术具有施工压力低、补贴效率高、工具性能可靠、操作简单等优点,有效解决了常规膨胀管不耐腐蚀、易生锈的缺点。②原内径为Ø124.26 mm的套管经传统方式补贴后通径为Ø108 mm左右,经薄壁大通径不锈钢膨胀管补贴后通径可达Ø116 mm、抗内压能力与经传统方式补贴后持平,有效满足了常规井下工具的后续下入需求,实现了真正意义上的套管大通径补贴修复。该项技术补充完善了膨胀管补贴工艺技术体系,为老井二次开发提供了新的大通径井筒修复手段。

墙式再热器管内壁腐蚀原因及其预防措施

某电厂300MW亚临界燃煤机组墙式再热器管发生了腐蚀穿孔现象。通过宏观检验、X射线荧光光谱分析、金相检查、扫描电镜及能谱检测等手段对腐蚀原因进行分析。结果表明:锅炉本身结构及停炉保护不当造成机组停运时少量冷凝水残留在穿墙管弯头及水平段底部,导致管内壁发生溶解氧腐蚀,最终腐蚀穿孔。针对上述事件,某发电集团对区域内机组进行排查,并从停炉操作过程、停备保护方法、水汽品质控制、日常检修维护等方面提出一系列预防措施。

30例新生儿先天性胃壁肌层缺损致胃穿孔的诊疗分析

目的:探讨新生儿先天性胃壁肌层缺损致胃穿孔的临床特点及诊疗措施,为新生儿先天性胃壁肌层缺损致胃穿孔的临床诊治提供参考依据。方法:选取2021年4月—2023年4月贵阳市妇幼保健院收治的30例新生儿先天性胃壁肌层缺损致胃穿孔患儿为研究对象,分析其临床资料。结果:30例患儿均接受手术治疗,治愈率为63.33%(19/30)。术后病理检查均提示先天性胃壁肌层缺损。放弃治疗11例。结论:对于新生儿先天性胃壁肌层缺损致胃穿孔,需根据患儿临床表现、病史、体征等明确诊断,对于诊断确切并符合手术指征的患儿,应积极进行手术探查,尽早发现病灶,将修补胃壁切除,积极矫正消化道畸形,同时进行抗休克、抗感染治疗,可降低病死率,提高手术疗效,促进患儿早日康复。

树脂嵌体修复磨牙髓室底穿孔的形态学及微渗漏研究

目的研究树脂嵌体修复离体人恒磨牙髓室底穿孔的形态学及封闭效果。方法将50颗新鲜拔除的离体人恒磨牙随机分为A、B、C3个实验组(每组15颗牙)和1个对照组(5颗牙)。制备髓室底穿孔后,A组采用树脂嵌体和AHPlus糊剂修复髓室底穿孔,B组采用树脂嵌体和玻璃离子修复髓室底穿孔,C组采用光固化复合树脂直接充填修复髓室底穿孔。对照组5颗离体牙,只开髓不制备髓室底穿孔。体视显微镜下观察髓室底穿孔修复后的外形恢复情况,葡萄糖氧化酶-蒽酮法测定微渗漏情况。结果嵌体法修复髓室底穿孔的形态恢复优良率为83.3%,直接充填法修复髓室底穿孔的形态恢复优良率为46.7%,两种方法修复的形态恢复优良率之间的差异有统计学意义(P<0.05)。3组在各个时间点上任意2组的日均葡萄糖浓度差异都有统计学意义,A组<B组<C组(P<0.05)。结论树脂嵌体修复髓室底穿孔在形态恢复和封闭性上都优于直接充填法,AHPlus糊剂对树脂嵌体的封闭能力优于玻璃离子。