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 perfor...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.展开更多
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 met...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.展开更多
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-select...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 1<sup>st</sup> January 2018 to 30<sup>th</sup> 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/m<sup>2</sup>. 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.展开更多
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 positi...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.展开更多
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...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.展开更多
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 sim...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.展开更多
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 ...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.展开更多
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,ulce...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.展开更多
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 engin...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.展开更多
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 ...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.展开更多
基金the Yildiz Technical University Research Fund for financially supporting this work
文摘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.
基金The Natural Science Foundation of Shandong Province under contract No.Q2008F01the Specialized Research Fund for the Doctoral Program of Higher Education under contract No.200804231006the Found of Shandong Province Key Laboratory of Ocean Engineering
文摘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.
文摘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 1<sup>st</sup> January 2018 to 30<sup>th</sup> 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/m<sup>2</sup>. 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.
文摘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.
文摘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.
文摘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.
文摘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.
文摘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.
文摘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.
文摘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.