An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc...An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.展开更多
BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limit...BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limited.AIM To evaluate surgical and survival outcomes of patients with perforated GC(PGC)according to the initial treatment strategy.METHODS A retrospective cohort study was conducted including all patients with pathologically confirmed perforated gastric adenocarcinoma treated at a single tertiary cancer center between January 2009 and March 2024.Surgical strategies were categorized as gastrectomy or primary perforation repair.Outcomes analyzed included 30-and 90-day mortality,postoperative major complications,and overall survival(OS).RESULTS Among 1586 GC patients undergoing surgical treatment,36(2.3%)presented with PGC.The mean age was 62.5 years,and 55%were male.American Society of Anesthesiologists(ASA)class III/IV was present in 58.3%,and 83%had stage IV disease,with distant metastasis in 50%.Perforation repair was performed in 26 patients(72.2%),while 10(27.8%)underwent one-stage gastrectomy.ASA III/IV status(57.7%vs 30%,P=0.260)and metastatic disease(57.7%vs 30%,P=0.137)were more frequent in the Perforation Repair Group,though not statistically significant.This group also had a higher rate of diffuse-type and poorly differentiated tumors(P=0.024 and P=0.014,respectively).Thirty-and 90-day mortality were higher in the Perforation Repair Group(61.5%vs 30%,P=0.139;and 65.4%vs 30%,P=0.073),without significance.Three patients initially repaired were later referred for gastrectomy.OS was significantly better in the Gastrectomy Group(P=0.002),with median survival of 8.8 months vs 0.5 months.On multivariable analysis,gastrectomy was independently associated with improved survival(P=0.026).CONCLUSION When clinically feasible,gastrectomy—either immediate or delayed—provides superior survival compared to local perforation repair alone in patients with PGC.展开更多
BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and ...BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and an ideal postoperative antiinfective approach for PPA management has yet to be established.AIM To examine the spectrum of pathogenic bacteria in pediatric PPA and to summarize the postoperative experience with carbapenem(CBP)and cephalosporin(CPS)antibiotics.METHODS We retrospectively analyzed medical records of 65 children(43 boys,22 girls;mean age 6.92±3.41 years)with PPA who underwent surgery at our hospital between December 2019 and August 2022.Data were collected in September 2023.Based on postoperative antibiotic selection,patients were divided into CBP(32 cases)and CPS(33 cases)groups.Chi-square and T-tests compared recovery outcomes,while univariate and multivariate regression models identified independent factors affecting postoperative recovery.RESULTS There were no significant differences between the two groups in gender,age,weight,height,body mass index,baseline ear temperature,or heart rate(P>0.05).Escherichia coli(40.00%)and Pseudomonas aeruginosa(24.62%)were the most common pathogens in PPA.Postoperative analysis showed significantly shorter C-reactive protein(CRP)recovery times in the CPS group than in the CBP group[(6.18±1.84)vs(8.12±3.48)days,P=0.009].Univariate logistic regression indicated CPS selection(OR=0.32,95%CI:0.10-0.97,P=0.044)was significantly associated with a higher CRP recovery rate within 7 days.Multivariate analysis confirmed CPS selection(OR=3.49,95%CI:1.19-10.24,P=0.023)as an independent factor affecting CRP recovery within 7 days postoperatively.CONCLUSION The choice of CBP or CPS independently affects CRP recovery within 7 days.CBP offers no advantage over CPS in treating PPA,with CPS also demonstrating favorable clinical outcomes.展开更多
BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the d...BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the diagnosis of preoperative PPU during pregnancy and puerperium challenging.AIM To identify predictive factors for early diagnosis and treatment,and the association between the diagnosis and maternal/neonatal outcomes.METHODS We searched PubMed,PubMed Central,and Google Scholar.Articles were analyzed following preferred reporting items for systematic reviews and metaanalysis.The search items included:‘ulcer’,‘PUD’,‘pregnancy’,‘puerperium’,‘postpartum’,‘gravid’,‘labor’,‘perforated ulcer’,‘stomach ulcer’,‘duodenal ulcer’,‘peptic ulcer’.Additional studies were extracted by reviewing reference lists of retrieved studies.We included all available full-text cases and case series.Demographic,clinical,obstetric,diagnostic and treatment parameters,and outcomes were collected.RESULTS Forty-three cases were collected.The mean maternal age was 30.9 years;36.6%were multiparous,and 63.4%were nulliparous or primiparous,with multiparas being older than primiparas.Peptic ulcer perforated in 44.2%of postpartum and 55.8%of antepartum patients.Antepartum PPU incidence increased with advancing gestation 2.3%in the first,7%in the second,and 46.5%in the third trimester.The most common clinical findings were abdominal tenderness(72.1%),rigidity(34.9%),and distension(48.8%).Duodenal ulcer predominated(76.7%).In 79.5%,the time from delivery to surgery or vice versa was>24 hours.The maternal mortality during the third trimester and postpartum was 10%and 31.6%,respectively.The trimester of presentation did not influence maternal mortality.The fetal mortality was 34.8%,with all deaths in gestational weeks 24-32.CONCLUSION Almost all patients with PPU in pregnancy or puerperium presented during the third trimester or the first 8 days postpartum.Early intervention reduced fetal mortality but without influence on maternal mortality.Maternal mortality did not depend on the use of X-ray imaging,perforation location,delivery type,trimester of presentation,and maternal age.Explorative laparoscopy was never performed during pregnancy,only postpartum.展开更多
In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool...In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.展开更多
Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,mo...Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,modifying current collectors with perforations,to address these issues.Lithium ion batteries with mechanically perforated current collectors are prepared and tested with charge/discharge cycles,revealing superior capacity as well as enhanced electrochemical stability over cycles.Impedance spectroscopy,scanning electron microscopy,and peeling tests are conducted to investigate the underlying mechanisms.Higher peel resistance,minimized interface cracking,and reduced electrical impedance are found in the perforated electrodes after cycles.Investigations indicate that the perforation holes on current collectors allow the active materials coating on the two sides of the current collector to bind together and,thus,lead to enhanced adhesion between the current collector and active layer.Mechanical simulation illustrates the role of perforated current collectors in curbing interface cracking during lithiation,while electrochemical simulation shows that the interfacial cracking hinders the diffusion of lithium ions,thereby increasing battery impedance and reducing the cyclic performance.This investigation reveals the potential of designing non-active battery components to enhance battery performance,advocating a nuanced approach to battery design emphasizing structural integrity and interface optimization.展开更多
In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle...In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle Fatigue(MLCF)life of perforated structures.First,fatigue tests are carried out on three center-perforated structures,aiming to assess their fatigue life under various strengthening conditions.These tests reveal significant variations in fatigue life,accompanied by an examination of crack initiation through the analysis of fatigue fracture surfaces.Second,an innovative fatigue life prediction methodology is applied to perforated structures,which not only forecasts the initiation of fatigue cracks but also traces the progression of damage within these structures.It leverages an elastoplastic constitutive model integrated with damage and a damage evolution model under cyclic loads.The accuracy of this approach is validated by comparison with test results,falling within the three times error band.Finally,we explore the impact of various strengthening techniques,including cross-sectional reinforcement and cold expansion,on the fatigue life and damage evolution of these structures.This is achieved through an in-depth comparative analysis of both experimental data and computational predictions,which provides valuable insights into the behavior of perforated structures under fatigue conditions in practical applications.展开更多
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex...The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.展开更多
BACKGROUND Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abd...BACKGROUND Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abdominal pain and peritoneal signs.By contrast,pneumoretroperitoneum and pneumomediastinum are rare complications and lack typical symptoms,making their diagnosis difficult and often delayed,leading to increased morbidity and mortality.CASE SUMMARY A 66-year-old man presented with lower abdominal pain for 3 days.On examination,his vital signs were stable,and the abdomen was soft with mild distension and left lower quadrant tenderness,but no peritoneal signs were noted.Laboratory tests indicated leukocytosis and a markedly elevated C-reactive protein level.Abdominal computed tomography(CT)revealed focal wall thickening and fat stranding near the rectosigmoid junction as well as pneumoretroperitoneum,pneumomediastinum,and minor pneumoperitoneum.Suspecting hollow organ perforation,an emergent exploratory laparotomy was performed which revealed a retroperitoneal abscess with mesocolonic necrosis,likely due to perforated sigmoid diverticulitis.The patient underwent sigmoid resection with Hartmann’s procedure and retroperitoneal drainage.Follow-up CT on postoperative day 14 confirmed resolution of the free air,and the patient was discharged on postoperative day 40 with an uneventful recovery.CONCLUSION Pneumoretroperitoneum and pneumomediastinum are rare complications of perforated diverticulitis,often with delayed diagnosis due to the absence of peritoneal signs.CT aids detection,and timely surgical intervention is crucial.展开更多
BACKGROUND Acute perforated cholecystitis(APC)is a serious complication of acute cholecystitis and is associated with significant morbidity and mortality,particularly in elderly or high-risk patients.While emergency c...BACKGROUND Acute perforated cholecystitis(APC)is a serious complication of acute cholecystitis and is associated with significant morbidity and mortality,particularly in elderly or high-risk patients.While emergency cholecystectomy is the standard of care,it may not be feasible in unstable patients.Percutaneous transhepatic cholecystostomy(PTC)offers a minimally invasive alternative.AIM To evaluate the safety and effectiveness of PTC as an initial treatment modality for APC.METHODS We conducted a retrospective cohort study of patients diagnosed with APC between January 2017 and October 2022 at a single tertiary medical center.All patients underwent PTC as the initial intervention.Data collected included demographics,comorbidities,laboratory and imaging findings,complications,and clinical outcomes over a 24-month follow-up.Patients were stratified into two groups based on whether they subsequently underwent cholecystectomy.RESULTS Thirty patients underwent PTC for APC.Half of the patients(n=15)were stabilized and later underwent cholecystectomy;the remaining 15 were managed non-operatively.Patients in the non-surgical group were significantly older(87.1±6.2 years vs 76.1±7.4 years;P<0.001).Clinical improvement was observed in 61.4%of non-operated patients,with eventual drain removal or closure.Both groups demonstrated significant reductions in white blood cell count and C-reactive protein levels from admission to discharge.No significant differences were found in hospital stay or complication rates.During follow-up,three deaths occurred due to non-biliary causes.Only one patient required repeat drainage.CONCLUSION PTC is a safe and effective initial treatment for APC,particularly in elderly and comorbid patients for whom surgery poses excessive risk.It provides clinical stabilization and may serve either as a bridge to delayed cholecystectomy or as definitive management in selected patients.These findings support the broader use of PTC in the management of APC,although larger prospective studies are warranted.展开更多
[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old ...[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old apple, pear, peach and grape trees as the materials, the author studied the absorption condition of these trees to six kinds of zinc substances and their security. The sealed curative effects of the injected zinc substances which were harmful and could be absorbed steadily by the fruit trees against rosette disease were studied. [ Result] The results of absorption condition and security experiments showed that only zinc-mmnonia complex could be absorbed steadily and safely throughout four seasons. When apple, pear, peach and grape trees affected by rosette disease were injected with zinc- ammonia complex, the leaves of those trees started to grow obviously after 10 d; the internodes of diseased branches elongated, the leaves turned bigger, and the ap- pearance of branches became normal after about 25 d. [ Conclusion] The curative effect of perforated injection of zinc-ammonia complex on fruit tree rosette disease was remarkable. The results also provided a new way for the cure of deficiency diseases of other trace elements.展开更多
AIM:To investigate the epidemiological trends in inci-dence and mortality of perforated peptic ulcer(PPU)in a well-defined Norwegian population. METHODS:A retrospective,population-based,single-center,consecutive cohor...AIM:To investigate the epidemiological trends in inci-dence and mortality of perforated peptic ulcer(PPU)in a well-defined Norwegian population. METHODS:A retrospective,population-based,single-center,consecutive cohort study of all patients diag-nosed with benign perforated peptic ulcer.Included were both gastric and duodenal ulcer patients admitted to Stavanger University Hospital between January 2001 and December 2010.Ulcers with a malignant neoplasia diagnosis,verified by histology after biopsy or resection,were excluded.Patients were identified from the hospitals administrative electronic database using pertinent ICD-9 and ICD-10 codes(K25.1,K25.2,K25.5, K25.6,K26.1,K26.2,K26.5,K26.6).Additional searches using appropriate codes for relevant laparoscopic and open surgical procedures(e.g.,JDA 60,JDA 61,JDH 70 and JDH 71)were performed to enable a complete identification of all patients.Patient demographics,presentation patterns and clinical data were retrieved from hospital records and surgical notes.Crude and adjusted incidence and mortality rates were estimated by using national population demographics data. RESULTS:In the study period,a total of 172 patients with PPU were identified.The adjusted incidence rate for the overall 10-year period was 6.5 per 100 000 per year(95%CI:5.6-7.6)and the adjusted mortality rate for the overall 10-year period was 1.1 per 100 000 per year(95%CI:0.7-1.6).A non-significant decline in ad-justed incidence rate from 9.7 to 5.6 occurred during the decade.The standardized mortality ratio for the whole study period was 5.7(95%CI:3.9-8.2),while the total 30-d mortality was 16.3%.No difference in in-cidence or mortality was found between genders.However,for patients≥60 years,the incidence increased over 10-fold,and mortality more than 50-fold,compared to younger ages.The admission rates outside office hours were high with almost two out of three(63%) admissions seen at evening/night time shifts and/or during weekends.The observed seasonal variations in admissions were not statistically significant. CONCLUSION:The adjusted incidence rate,seasonal distribution and mortality rate was stable.PPU fre-quently presents outside regular work-hours.Increase in incidence and mortality occurs with older age.展开更多
The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to e...The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to expand velocity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results of the present model are compared with experimental data. The effect of porosity, the relative chamber width, the relative water depth in the wave absorbing chamber and the water depth in front of the structure are discussed.展开更多
A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this expe...A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this experimental rig to estimate the free surface fluctuation and pressure distribution by changing external excitation frequency of the shaking table. An in-house CFD code is also used in this study to simulate the liquid sloshing in three-dimensional （3D） rectangular tank with perforated baffle. Good agreements of free surface elevation and pressure between the numerical results and the experimental data are obtained and presented. Spectral analysis of the time history of free surface elevation is conducted by using the fast Fourier transformation.展开更多
The effectiveness of perforated liner with bias flow on the control of combustion instability is investigated. Combustion instabilities result from the coupling between acoustic waves and unsteady combustion heat rele...The effectiveness of perforated liner with bias flow on the control of combustion instability is investigated. Combustion instabilities result from the coupling between acoustic waves and unsteady combustion heat release. Sometimes the phenomenon happens in afterburners of aeroengine and rocket engine, and it always causes damage to flame holders, liner seetions and other engine components. Passive methods, such as perforated liner, are often used to suppress such instabilities in application. In this article, first, a burner testbed is built in order to study the characteristic of this phenomenon. The unstable frequencies and unsta- ble area are investigated experimentally. Then an analytical model, based on "transfer element method", is developed and the numerical results are compared with those from experiments. At last the perforated liner is applied to the burner to suppress the instabilities. The results show that the sound pressure can be greatly reduced by the perforated liner.展开更多
A time-domain method, based on linear velocity potential theory, is presented to study the interaction between narrow-banded random waves and perforated structures. A simple relation is derived to estimate the jet len...A time-domain method, based on linear velocity potential theory, is presented to study the interaction between narrow-banded random waves and perforated structures. A simple relation is derived to estimate the jet length of flows through the perforated wall. The reflection coefficient of narrow banded random waves from perforated structures is calculated by assuming a Rayleigh distribution of the heights of incident random waves. For reflection of narrow-banded waves from a single-chamber perforated breakwater, a comparison of the predicted and measured reflection coefficients shows that the method presented in this paper can provide a prediction better than that of regular waves. Numerical results are also reported on the reflection of narrow-banded waves from multi-chamber perforated breakwaters.展开更多
An analytical method is developed to study the sheltering effects on arc-shaped floating perforated breakwaters. In the process of analysis, the tloating breakwater is assumed to be rigid, thin, vertical, and immovabl...An analytical method is developed to study the sheltering effects on arc-shaped floating perforated breakwaters. In the process of analysis, the tloating breakwater is assumed to be rigid, thin, vertical, and immovable and located in water with constant depth. The fluid domain is divided into two regions by imaginary interface. The velocity potential in each region is expanded by eigenfunction in the context of linear theory. By satisfying continuity of pressure and normal velocity across the imaginary fluid interface, a set of linear algebraic equations can be obtained to determine the unknown coefficients for eigenfunction expansions. The accuracy of the present model was verified by a comparison with existing results for the case of arc-shaped floating breakwater. Numerical results, in the form of contour maps of the non-dimensional wave amplitude around the breakwater and diffracted wave amplitude at typical sections, are presented for a range of wave and breakwater parameters. Results show that the sheltering effects on the arc-shaped floating perforated breakwater are closely related to the incident wavelength, the draft and the porosity of the breakwater.展开更多
In this study examined is the wave interaction with a new modified perforated breakwater, consisting of a perforated front wall, a solid back wall and a wave absorbing chamber between them with a two-layer rock-filled...In this study examined is the wave interaction with a new modified perforated breakwater, consisting of a perforated front wall, a solid back wall and a wave absorbing chamber between them with a two-layer rock-filled core. The fluid domain is divided into three sub-domains according to the components of the breakwater. Then by means of the matched eigenfunction expansion method, an analytical solution is obtained to assess the hydrodynamic performance of the new structure. An approach based on a step approach method is introduced to solve the complex dispersion equations for water wave motions within two-layer porous media. Numerical results of the present model are compared with previous limiting cases. The effects of rock fill on the reflec- tion coefficient and the horizontal wave force are discussed.展开更多
While pneumatosis cystoides intestinalis （PCI） is a rare disease entity associated with a wide variety of gastrointestinal and non-gastrointestinal disorders, PCI associated with massive intra- and retroperitoneal f...While pneumatosis cystoides intestinalis （PCI） is a rare disease entity associated with a wide variety of gastrointestinal and non-gastrointestinal disorders, PCI associated with massive intra- and retroperitoneal free air is extremely uncommon, and is difficult to diagnose differentially from perforated peritonitis. We present two cases of PCI associated with massive peritoneal free air and/or retroperitoneal air that mimicked perforated peritonitis. These cases highlight the clinical importance of PCI that mimics perforated peritonitis, which requires emergency surgery. Preoperative imaging modalities and diagnostic laparoscopy are useful to make an accurate diagnosis.展开更多
The volume of fluid (VOF) method is presented to determine the reflection coefficient of and the total horizontal wave force on perforated caisson breakwaters. The present numerical model is compared with a linear ana...The volume of fluid (VOF) method is presented to determine the reflection coefficient of and the total horizontal wave force on perforated caisson breakwaters. The present numerical model is compared with a linear analytic solution obtained by Sahoo et al. (2000). Also this model is verified with the authors′ laboratory data. It is found that the numerical model is in good agreement with the regression equations obtained from the experimental data. The present numerical method is further discussed to relate porosity, the relative wave absorbing chamber depth, the reflection coefficient of perforated caissons and the total horizontal force on them.展开更多
基金Open access funding provided by FCT|FCCN(b-on)the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020.
文摘An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.
文摘BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limited.AIM To evaluate surgical and survival outcomes of patients with perforated GC(PGC)according to the initial treatment strategy.METHODS A retrospective cohort study was conducted including all patients with pathologically confirmed perforated gastric adenocarcinoma treated at a single tertiary cancer center between January 2009 and March 2024.Surgical strategies were categorized as gastrectomy or primary perforation repair.Outcomes analyzed included 30-and 90-day mortality,postoperative major complications,and overall survival(OS).RESULTS Among 1586 GC patients undergoing surgical treatment,36(2.3%)presented with PGC.The mean age was 62.5 years,and 55%were male.American Society of Anesthesiologists(ASA)class III/IV was present in 58.3%,and 83%had stage IV disease,with distant metastasis in 50%.Perforation repair was performed in 26 patients(72.2%),while 10(27.8%)underwent one-stage gastrectomy.ASA III/IV status(57.7%vs 30%,P=0.260)and metastatic disease(57.7%vs 30%,P=0.137)were more frequent in the Perforation Repair Group,though not statistically significant.This group also had a higher rate of diffuse-type and poorly differentiated tumors(P=0.024 and P=0.014,respectively).Thirty-and 90-day mortality were higher in the Perforation Repair Group(61.5%vs 30%,P=0.139;and 65.4%vs 30%,P=0.073),without significance.Three patients initially repaired were later referred for gastrectomy.OS was significantly better in the Gastrectomy Group(P=0.002),with median survival of 8.8 months vs 0.5 months.On multivariable analysis,gastrectomy was independently associated with improved survival(P=0.026).CONCLUSION When clinically feasible,gastrectomy—either immediate or delayed—provides superior survival compared to local perforation repair alone in patients with PGC.
基金Supported by Jiaxing Science and Technology Plan Project,No.2024AD30035.
文摘BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and an ideal postoperative antiinfective approach for PPA management has yet to be established.AIM To examine the spectrum of pathogenic bacteria in pediatric PPA and to summarize the postoperative experience with carbapenem(CBP)and cephalosporin(CPS)antibiotics.METHODS We retrospectively analyzed medical records of 65 children(43 boys,22 girls;mean age 6.92±3.41 years)with PPA who underwent surgery at our hospital between December 2019 and August 2022.Data were collected in September 2023.Based on postoperative antibiotic selection,patients were divided into CBP(32 cases)and CPS(33 cases)groups.Chi-square and T-tests compared recovery outcomes,while univariate and multivariate regression models identified independent factors affecting postoperative recovery.RESULTS There were no significant differences between the two groups in gender,age,weight,height,body mass index,baseline ear temperature,or heart rate(P>0.05).Escherichia coli(40.00%)and Pseudomonas aeruginosa(24.62%)were the most common pathogens in PPA.Postoperative analysis showed significantly shorter C-reactive protein(CRP)recovery times in the CPS group than in the CBP group[(6.18±1.84)vs(8.12±3.48)days,P=0.009].Univariate logistic regression indicated CPS selection(OR=0.32,95%CI:0.10-0.97,P=0.044)was significantly associated with a higher CRP recovery rate within 7 days.Multivariate analysis confirmed CPS selection(OR=3.49,95%CI:1.19-10.24,P=0.023)as an independent factor affecting CRP recovery within 7 days postoperatively.CONCLUSION The choice of CBP or CPS independently affects CRP recovery within 7 days.CBP offers no advantage over CPS in treating PPA,with CPS also demonstrating favorable clinical outcomes.
文摘BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the diagnosis of preoperative PPU during pregnancy and puerperium challenging.AIM To identify predictive factors for early diagnosis and treatment,and the association between the diagnosis and maternal/neonatal outcomes.METHODS We searched PubMed,PubMed Central,and Google Scholar.Articles were analyzed following preferred reporting items for systematic reviews and metaanalysis.The search items included:‘ulcer’,‘PUD’,‘pregnancy’,‘puerperium’,‘postpartum’,‘gravid’,‘labor’,‘perforated ulcer’,‘stomach ulcer’,‘duodenal ulcer’,‘peptic ulcer’.Additional studies were extracted by reviewing reference lists of retrieved studies.We included all available full-text cases and case series.Demographic,clinical,obstetric,diagnostic and treatment parameters,and outcomes were collected.RESULTS Forty-three cases were collected.The mean maternal age was 30.9 years;36.6%were multiparous,and 63.4%were nulliparous or primiparous,with multiparas being older than primiparas.Peptic ulcer perforated in 44.2%of postpartum and 55.8%of antepartum patients.Antepartum PPU incidence increased with advancing gestation 2.3%in the first,7%in the second,and 46.5%in the third trimester.The most common clinical findings were abdominal tenderness(72.1%),rigidity(34.9%),and distension(48.8%).Duodenal ulcer predominated(76.7%).In 79.5%,the time from delivery to surgery or vice versa was>24 hours.The maternal mortality during the third trimester and postpartum was 10%and 31.6%,respectively.The trimester of presentation did not influence maternal mortality.The fetal mortality was 34.8%,with all deaths in gestational weeks 24-32.CONCLUSION Almost all patients with PPU in pregnancy or puerperium presented during the third trimester or the first 8 days postpartum.Early intervention reduced fetal mortality but without influence on maternal mortality.Maternal mortality did not depend on the use of X-ray imaging,perforation location,delivery type,trimester of presentation,and maternal age.Explorative laparoscopy was never performed during pregnancy,only postpartum.
基金supported by the National Natural Science Foundation of China(Project No.52166004)the National Key Research and Development Program of China(Project No.2022YFC3902000)+2 种基金the Major Science and Technology Special Project of Yunnan Province(Project Nos.202202AG050007202202AG050002)the Research on the Development of Complete Sets of Technology for Extraction of Aromatic Substances from Tobacco Waste and Its Application,Applied Research-Pyrolysis Process Technology Research(2023QT01).
文摘In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.
基金supported by the National Natural Science Foundation of China under Grant Nos.12172205,11872236,and 12072183.
文摘Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,modifying current collectors with perforations,to address these issues.Lithium ion batteries with mechanically perforated current collectors are prepared and tested with charge/discharge cycles,revealing superior capacity as well as enhanced electrochemical stability over cycles.Impedance spectroscopy,scanning electron microscopy,and peeling tests are conducted to investigate the underlying mechanisms.Higher peel resistance,minimized interface cracking,and reduced electrical impedance are found in the perforated electrodes after cycles.Investigations indicate that the perforation holes on current collectors allow the active materials coating on the two sides of the current collector to bind together and,thus,lead to enhanced adhesion between the current collector and active layer.Mechanical simulation illustrates the role of perforated current collectors in curbing interface cracking during lithiation,while electrochemical simulation shows that the interfacial cracking hinders the diffusion of lithium ions,thereby increasing battery impedance and reducing the cyclic performance.This investigation reveals the potential of designing non-active battery components to enhance battery performance,advocating a nuanced approach to battery design emphasizing structural integrity and interface optimization.
基金support from the National Natural Science Foundation of China(No.12472072)the Fundamental Research Funds for the Central Universities,China.
文摘In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle Fatigue(MLCF)life of perforated structures.First,fatigue tests are carried out on three center-perforated structures,aiming to assess their fatigue life under various strengthening conditions.These tests reveal significant variations in fatigue life,accompanied by an examination of crack initiation through the analysis of fatigue fracture surfaces.Second,an innovative fatigue life prediction methodology is applied to perforated structures,which not only forecasts the initiation of fatigue cracks but also traces the progression of damage within these structures.It leverages an elastoplastic constitutive model integrated with damage and a damage evolution model under cyclic loads.The accuracy of this approach is validated by comparison with test results,falling within the three times error band.Finally,we explore the impact of various strengthening techniques,including cross-sectional reinforcement and cold expansion,on the fatigue life and damage evolution of these structures.This is achieved through an in-depth comparative analysis of both experimental data and computational predictions,which provides valuable insights into the behavior of perforated structures under fatigue conditions in practical applications.
基金funded by the Project of the Hubei Provincial Department of Science and Technology(Grant No.2022CFB957)the Project of Hubei Engineering University of Teaching Research(Grant No.JY2024032)+1 种基金Ministry of Education University-Industry Cooperation Collaborative Education Project(Grant No.220903584161245)College Students’Innovation and Entrepreneurship Training Program(Grant Nos.DC2024031,DC2024032).
文摘The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.
文摘BACKGROUND Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abdominal pain and peritoneal signs.By contrast,pneumoretroperitoneum and pneumomediastinum are rare complications and lack typical symptoms,making their diagnosis difficult and often delayed,leading to increased morbidity and mortality.CASE SUMMARY A 66-year-old man presented with lower abdominal pain for 3 days.On examination,his vital signs were stable,and the abdomen was soft with mild distension and left lower quadrant tenderness,but no peritoneal signs were noted.Laboratory tests indicated leukocytosis and a markedly elevated C-reactive protein level.Abdominal computed tomography(CT)revealed focal wall thickening and fat stranding near the rectosigmoid junction as well as pneumoretroperitoneum,pneumomediastinum,and minor pneumoperitoneum.Suspecting hollow organ perforation,an emergent exploratory laparotomy was performed which revealed a retroperitoneal abscess with mesocolonic necrosis,likely due to perforated sigmoid diverticulitis.The patient underwent sigmoid resection with Hartmann’s procedure and retroperitoneal drainage.Follow-up CT on postoperative day 14 confirmed resolution of the free air,and the patient was discharged on postoperative day 40 with an uneventful recovery.CONCLUSION Pneumoretroperitoneum and pneumomediastinum are rare complications of perforated diverticulitis,often with delayed diagnosis due to the absence of peritoneal signs.CT aids detection,and timely surgical intervention is crucial.
文摘BACKGROUND Acute perforated cholecystitis(APC)is a serious complication of acute cholecystitis and is associated with significant morbidity and mortality,particularly in elderly or high-risk patients.While emergency cholecystectomy is the standard of care,it may not be feasible in unstable patients.Percutaneous transhepatic cholecystostomy(PTC)offers a minimally invasive alternative.AIM To evaluate the safety and effectiveness of PTC as an initial treatment modality for APC.METHODS We conducted a retrospective cohort study of patients diagnosed with APC between January 2017 and October 2022 at a single tertiary medical center.All patients underwent PTC as the initial intervention.Data collected included demographics,comorbidities,laboratory and imaging findings,complications,and clinical outcomes over a 24-month follow-up.Patients were stratified into two groups based on whether they subsequently underwent cholecystectomy.RESULTS Thirty patients underwent PTC for APC.Half of the patients(n=15)were stabilized and later underwent cholecystectomy;the remaining 15 were managed non-operatively.Patients in the non-surgical group were significantly older(87.1±6.2 years vs 76.1±7.4 years;P<0.001).Clinical improvement was observed in 61.4%of non-operated patients,with eventual drain removal or closure.Both groups demonstrated significant reductions in white blood cell count and C-reactive protein levels from admission to discharge.No significant differences were found in hospital stay or complication rates.During follow-up,three deaths occurred due to non-biliary causes.Only one patient required repeat drainage.CONCLUSION PTC is a safe and effective initial treatment for APC,particularly in elderly and comorbid patients for whom surgery poses excessive risk.It provides clinical stabilization and may serve either as a bridge to delayed cholecystectomy or as definitive management in selected patients.These findings support the broader use of PTC in the management of APC,although larger prospective studies are warranted.
文摘[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old apple, pear, peach and grape trees as the materials, the author studied the absorption condition of these trees to six kinds of zinc substances and their security. The sealed curative effects of the injected zinc substances which were harmful and could be absorbed steadily by the fruit trees against rosette disease were studied. [ Result] The results of absorption condition and security experiments showed that only zinc-mmnonia complex could be absorbed steadily and safely throughout four seasons. When apple, pear, peach and grape trees affected by rosette disease were injected with zinc- ammonia complex, the leaves of those trees started to grow obviously after 10 d; the internodes of diseased branches elongated, the leaves turned bigger, and the ap- pearance of branches became normal after about 25 d. [ Conclusion] The curative effect of perforated injection of zinc-ammonia complex on fruit tree rosette disease was remarkable. The results also provided a new way for the cure of deficiency diseases of other trace elements.
文摘AIM:To investigate the epidemiological trends in inci-dence and mortality of perforated peptic ulcer(PPU)in a well-defined Norwegian population. METHODS:A retrospective,population-based,single-center,consecutive cohort study of all patients diag-nosed with benign perforated peptic ulcer.Included were both gastric and duodenal ulcer patients admitted to Stavanger University Hospital between January 2001 and December 2010.Ulcers with a malignant neoplasia diagnosis,verified by histology after biopsy or resection,were excluded.Patients were identified from the hospitals administrative electronic database using pertinent ICD-9 and ICD-10 codes(K25.1,K25.2,K25.5, K25.6,K26.1,K26.2,K26.5,K26.6).Additional searches using appropriate codes for relevant laparoscopic and open surgical procedures(e.g.,JDA 60,JDA 61,JDH 70 and JDH 71)were performed to enable a complete identification of all patients.Patient demographics,presentation patterns and clinical data were retrieved from hospital records and surgical notes.Crude and adjusted incidence and mortality rates were estimated by using national population demographics data. RESULTS:In the study period,a total of 172 patients with PPU were identified.The adjusted incidence rate for the overall 10-year period was 6.5 per 100 000 per year(95%CI:5.6-7.6)and the adjusted mortality rate for the overall 10-year period was 1.1 per 100 000 per year(95%CI:0.7-1.6).A non-significant decline in ad-justed incidence rate from 9.7 to 5.6 occurred during the decade.The standardized mortality ratio for the whole study period was 5.7(95%CI:3.9-8.2),while the total 30-d mortality was 16.3%.No difference in in-cidence or mortality was found between genders.However,for patients≥60 years,the incidence increased over 10-fold,and mortality more than 50-fold,compared to younger ages.The admission rates outside office hours were high with almost two out of three(63%) admissions seen at evening/night time shifts and/or during weekends.The observed seasonal variations in admissions were not statistically significant. CONCLUSION:The adjusted incidence rate,seasonal distribution and mortality rate was stable.PPU fre-quently presents outside regular work-hours.Increase in incidence and mortality occurs with older age.
基金by Joint Fund of the National Natural Science Foundation of China the Hong Kong Science Research Bureau (49910161985)+1 种基金the National Natural Science Foundation of China (50025924,50179004)the Research Fund for the Development of harbor engineeri
文摘The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to expand velocity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results of the present model are compared with experimental data. The effect of porosity, the relative chamber width, the relative water depth in the wave absorbing chamber and the water depth in front of the structure are discussed.
基金supported by the China Postdoctoral Science Foundation(Grant No.2012M511192)the National Natural Science Foundation of China(Grant Nos.51209080 and 51061130547+5 种基金Open Fund of State Key Laboratory of Coastaland Off shore Engineering(Grant No.LP1207the Open Fund of State Key Laboratory of Hydraulics and Mountain River Engineering(Grant No.1213)Qing Lan Project and 333 Project of Jiangsu Province(Grant No.BRA2012130)the Fundamental Research Funds for the Central Universities(Hohai University,Grant No.2012B06514the 111 Project(Grant No.B12032)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120181110084)
文摘A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this experimental rig to estimate the free surface fluctuation and pressure distribution by changing external excitation frequency of the shaking table. An in-house CFD code is also used in this study to simulate the liquid sloshing in three-dimensional （3D） rectangular tank with perforated baffle. Good agreements of free surface elevation and pressure between the numerical results and the experimental data are obtained and presented. Spectral analysis of the time history of free surface elevation is conducted by using the fast Fourier transformation.
基金National Natural Science Foundation of China (50890181)Aeronautical Science Foundation of China (2009ZB51)
文摘The effectiveness of perforated liner with bias flow on the control of combustion instability is investigated. Combustion instabilities result from the coupling between acoustic waves and unsteady combustion heat release. Sometimes the phenomenon happens in afterburners of aeroengine and rocket engine, and it always causes damage to flame holders, liner seetions and other engine components. Passive methods, such as perforated liner, are often used to suppress such instabilities in application. In this article, first, a burner testbed is built in order to study the characteristic of this phenomenon. The unstable frequencies and unsta- ble area are investigated experimentally. Then an analytical model, based on "transfer element method", is developed and the numerical results are compared with those from experiments. At last the perforated liner is applied to the burner to suppress the instabilities. The results show that the sound pressure can be greatly reduced by the perforated liner.
基金The project partially supported by the Hong Kong Research Grant Council (DAG03/04.EG39, DAG04/05.EG32)
文摘A time-domain method, based on linear velocity potential theory, is presented to study the interaction between narrow-banded random waves and perforated structures. A simple relation is derived to estimate the jet length of flows through the perforated wall. The reflection coefficient of narrow banded random waves from perforated structures is calculated by assuming a Rayleigh distribution of the heights of incident random waves. For reflection of narrow-banded waves from a single-chamber perforated breakwater, a comparison of the predicted and measured reflection coefficients shows that the method presented in this paper can provide a prediction better than that of regular waves. Numerical results are also reported on the reflection of narrow-banded waves from multi-chamber perforated breakwaters.
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.Bk2006013)the foundation of the State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University(Grant No.0907)the foundation of Engineering Institute of Engineering Corps and PLA University of Science & Technology
文摘An analytical method is developed to study the sheltering effects on arc-shaped floating perforated breakwaters. In the process of analysis, the tloating breakwater is assumed to be rigid, thin, vertical, and immovable and located in water with constant depth. The fluid domain is divided into two regions by imaginary interface. The velocity potential in each region is expanded by eigenfunction in the context of linear theory. By satisfying continuity of pressure and normal velocity across the imaginary fluid interface, a set of linear algebraic equations can be obtained to determine the unknown coefficients for eigenfunction expansions. The accuracy of the present model was verified by a comparison with existing results for the case of arc-shaped floating breakwater. Numerical results, in the form of contour maps of the non-dimensional wave amplitude around the breakwater and diffracted wave amplitude at typical sections, are presented for a range of wave and breakwater parameters. Results show that the sheltering effects on the arc-shaped floating perforated breakwater are closely related to the incident wavelength, the draft and the porosity of the breakwater.
基金The project supported by the Program for Changjiang ScholarsInnovative Research Teams in Universities(IRT0420)
文摘In this study examined is the wave interaction with a new modified perforated breakwater, consisting of a perforated front wall, a solid back wall and a wave absorbing chamber between them with a two-layer rock-filled core. The fluid domain is divided into three sub-domains according to the components of the breakwater. Then by means of the matched eigenfunction expansion method, an analytical solution is obtained to assess the hydrodynamic performance of the new structure. An approach based on a step approach method is introduced to solve the complex dispersion equations for water wave motions within two-layer porous media. Numerical results of the present model are compared with previous limiting cases. The effects of rock fill on the reflec- tion coefficient and the horizontal wave force are discussed.
文摘While pneumatosis cystoides intestinalis （PCI） is a rare disease entity associated with a wide variety of gastrointestinal and non-gastrointestinal disorders, PCI associated with massive intra- and retroperitoneal free air is extremely uncommon, and is difficult to diagnose differentially from perforated peritonitis. We present two cases of PCI associated with massive peritoneal free air and/or retroperitoneal air that mimicked perforated peritonitis. These cases highlight the clinical importance of PCI that mimics perforated peritonitis, which requires emergency surgery. Preoperative imaging modalities and diagnostic laparoscopy are useful to make an accurate diagnosis.
文摘The volume of fluid (VOF) method is presented to determine the reflection coefficient of and the total horizontal wave force on perforated caisson breakwaters. The present numerical model is compared with a linear analytic solution obtained by Sahoo et al. (2000). Also this model is verified with the authors′ laboratory data. It is found that the numerical model is in good agreement with the regression equations obtained from the experimental data. The present numerical method is further discussed to relate porosity, the relative wave absorbing chamber depth, the reflection coefficient of perforated caissons and the total horizontal force on them.
