leakage characteristics
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2022 ◽  
Vol 245 ◽  
pp. 110457
Author(s):  
Siyao Shao ◽  
Jiaqi Li ◽  
Kyungduck Yoon ◽  
Jiarong Hong

2022 ◽  
Vol 12 (2) ◽  
pp. 690
Author(s):  
Su-Young Choi ◽  
Dong-Bum Kim ◽  
Wan-Goo Park ◽  
Jin-Sang Park ◽  
Sang-Keun Oh

This study analyzed the characteristics of viscosity change and oil leakage stability according to the average particle size and content of organic and mineral-based extenders such as CaCO3(CA) and anti-sedimentation (ASE) among materials consisting of bituminous emulsion mastic (BEM). The fabrication of samples for research was done using a melting method of 2L capacity with the production mixing ratio of BEM used in the actual manufacturing process as a standard mixing ratio. Each sample size was adjusted to 16 μm, 5 μm, 2 μm, 1.4 μm and 1 μm, the average particle size of CA as a variable, and the content of ASE for each particle size was set to increase from 1 to 6 times the standard mixing ratio. The analysis found that in all average particle sizes of CA, the viscosity increased as the content of anti-sedimentation increased, and the viscosity was highest at the CA average particle size of 16 μm. The viscosity increased as the average particle size decreased at 5 μm, 2 μm, 1.4 μm and 1 μm. In addition, it was confirmed that the oil leakage stability increased as the average particle size of CA decreased, and the content of ASE increased. The evaluation results showed that specimens that met both workability and oil leakage stability conditions were the specimens with 4 times and 5 times the ASE content at the CA average particle size of 2 μm, and those with twice the ASE content at the CA average particle size of 1.4 μm.


Fuel ◽  
2022 ◽  
Vol 308 ◽  
pp. 122044
Author(s):  
Zheng Shang ◽  
Haifeng Wang ◽  
Bing Li ◽  
Yuanping Cheng ◽  
Xinghua Zhang ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lvjun Qing ◽  
Lichen Gu ◽  
Yan Wang ◽  
Zhufeng Lei

Purpose This paper aims to revel the leakage characteristics of the bent-axis piston pump considering elastohydrodynamic deformation via a dynamic leakage model. Design/methodology/approach A dynamic leakage model of bent-axis piston pump based on elastohydrodynamic lubrication theory is proposed, which is used to present the leakage characteristics of bent-axis piston pump. The model is composed of three parts. First, the dynamic gap in the piston ring-cylinder bore interface (PRCB) is described via the elastohydrodynamic lubrication equations. Then, the PRCB leakage is presented based on the dynamic gap. Finally, combined with leakage equation of the valve plate-cylinder block interface (VPCB), the total leakage model is proposed. Through the numerical simulation and experiment, the leakage characteristics of bent-axis piston pump considering elasto-hydrodynamic deformation are studied. Findings The PRCB leakage is negatively correlated with VPCB leakage under the range of 800–1400 r/min and 1–25 MPa. When the discharge pressure is less than the critical pressure, the PRCB leakage is the main factor affecting the total leakage in bent-axis piston pump. On the contrary, the VPCB leakage is the main factor. The critical pressure increases with increasing speed Originality/value The effect of operating parameters has a significant effect on the elastic deformation of piston ring without considering wear of friction pairs in bent-axis piston pump. There is a critical phenomenon in the leakage, which is related to the operating parameters, and provides a novel idea for extracting wear information from leakage and evaluating the status of bent-piston pump.


2021 ◽  
Vol 11 (21) ◽  
pp. 10312
Author(s):  
Goonho Kim ◽  
Jee-Hun Jeong ◽  
Hyun-Jeong Bang ◽  
Ho-Jun Lee

When estimating the theoretical hold time of a Clean Extinguishing Agent (CEA), the hold time is predicted using a leakage exponent and leakage characteristics that are measured through an Enclosure Integrity Test (EIT). In particular, the leakage exponent n is conventionally applied as 0.5, but recently, a variable exponent has been applied through measurement (approximately 0.48 to 0.85). When variable n is applied, the hold time varies greatly depending on the size of n. Therefore, in this study, a modified theoretical model for the hold time of a CEA is proposed to improve the accuracy of the hold time depending on the leakage exponent n. The modified theoretical model applies a different analysis of the inflow and outflow volumetric flow, and the results enable a more accurate hold time prediction. The modified theoretical equation shows an improvement of up to 8.6% for outflow volumetric flow V˙o and a maximum improvement of approximately 10.7% for hold time th.


2021 ◽  
Vol 2101 (1) ◽  
pp. 012021
Author(s):  
Rui Huang ◽  
Junming Cheng ◽  
Tian xia ◽  
Quanke Feng

Abstract In this paper, the piston clearance leakage model in reciprocating labyrinth compressor is established, and the leakage characteristics of labyrinth piston are analysed. The results show that in the labyrinth entrance section, the gas velocity decreases greatly, and the throttling effect is the most obvious. In the middle section of the labyrinth, the flow velocity descending gradient decreases. In the exit section, the flow rate begins to increase. When the labyrinth clearance is less than or equal to 0.1 mm, the clearance changes has little effect on the leakage. When the clearance is greater than 0.1 mm, the leakage increases rapidly with the clearance increasing. When the piston operates eccentrically, the leakage will increase by 1.5 ∼ 2 times compared with the non-eccentric operation. Therefore, the eccentric operation of the piston should be avoided as much as possible and the clearance should be reduced.


2021 ◽  
Vol 34 (Supplement_1) ◽  
Author(s):  
Sander Ubels ◽  
Moniek Verstegen ◽  
Stefan Bouwense ◽  
Gerjon Hannink ◽  
Bastiaan Klarenbeek ◽  
...  

Abstract   Anastomotic leakage (AL) is a common and potentially life-threatening complication after esophagectomy. In patients with AL it is largely unknown which patient parameters and leakage characteristics are associated with leak severity and mortality. We aimed to identify prognostic factors for mortality in patients with anastomotic leakage after esophagectomy. Methods The TENTACLE—Esophagus study is an international retrospective cohort study, in which 1451 patients with AL after esophagectomy between 2011 and 2019 were included in 71 centers from 20 countries. Potential prognostic factors were selected from literature and a hypothetical association with mortality. Confounders of (individual) prognostic factors were identified using a directed acyclic graph approach to minimize bias. Primary outcome was 90-day mortality. Logistic regression analysis was performed to estimate crude and adjusted odds ratios (AOR) and 95% confidence intervals (95%CI). The study protocol is accessible at www.tentaclestudy.com. Results Overall 90-day mortality rate was 11.6%. Leakage characteristics with the largest prognostic effect on mortality were gastric conduit ischemia/necrosis (AOR 2.23, 95%CI 1.43-3.49), defect circumference ≥ 25% (AOR 2.10, 95%CI 1.32-3.36) and intrathoracic fluid collections (drained AOR 1.98, 95%CI 1.05-3.75; undrained AOR 2.43, 95%CI 1.57-3.75). Patient parameters with the largest prognostic effect were ASA-score ≥ 3 (AOR 4.18, 95%CI 1.67-10.51), ECOG-score ≥ 2 (AOR 2.83, 95%CI 1.56-5.14) and respiratory failure (AOR 3.89, 95%CI 2.67-5.66), hemodynamic failure (AOR 3.09, 95%CI 1.96-4.88) or renal failure (AOR 4.08, 95%CI 2.20-7.59) at time of AL diagnosis. Conclusion Defect circumference, intrathoracic fluid collections, gastric conduit condition and several patient parameters were identified as prognostic factors for mortality in patients with AL. Adjusting for these prognostic factors may reduce confounding bias in future studies assessing efficacy of AL treatments. The identified prognostic factors contribute to the understanding of the severity of anastomotic leakage after esophagectomy and may be used to recognize the severity of an anastomotic leak in individual patients.


2021 ◽  
Vol 34 (Supplement_1) ◽  
Author(s):  
Sander Ubels ◽  
Moniek Verstegen ◽  
Stefan Bouwense ◽  
Gerjon Hannink ◽  
Peter Siersema ◽  
...  

Abstract   Anastomotic leakage (AL) is a common and severe complication after esophagectomy. It is largely unknown which primary treatments are most effective for which type of leak. We aimed to investigate the effectiveness of different primary treatments of AL. Methods International retrospective cohort study, in which patients with AL after esophagectomy with gastric tube reconstruction were included in the period 2011-2019. Detailed data regarding case mix, resection, leakage characteristics (e.g. organ failure, leak circumference, contamination, drains present) and leakage treatment (e.g. hours from diagnosis to treatment, primary and secondary treatment modalities) were collected. Primary outcome was 90-day mortality and secondary outcomes included length of stay and leak healing time. Different clinically relevant leakage groups have been defined. Efficacy of different treatment strategies adjusted for leakage severity will be analyzed in these clinical groups. The study protocol is accessible at www.tentaclestudy.com. Results Detailed data of 1451 patients with AL was collected from 71 centers in 20 countries. Data accuracy was 96.5%. Preliminary results showed that the overall 90-day mortality was 11.6%. The analysis of TENTACLE—Esophagus data is currently being performed and efficacy of different leakage treatment strategies is being assessed. The efficacy of initial leakage treatment strategies will be ready to be presented at the ISDE meeting. Conclusion This is the largest study on effectiveness of AL treatments. The final results of initial leak treatments, which will be available for presentation at the ISDE meeting, could provide an evidence-based basis that can be used by clinicians to determine the preferred primary treatment strategy in patients with a given type of anastomotic leakage.


2021 ◽  
Vol 34 (Supplement_1) ◽  
Author(s):  
Sander Ubels ◽  
Moniek Verstegen ◽  
Stefan Bouwense ◽  
Gerjon Hannink ◽  
Peter Siersema ◽  
...  

Abstract   Anastomotic leakage is a common and severe complication after esophagectomy. It is largely unknown which characteristics contribute to leakage severity. We aimed to investigate which factors are associated with leakage severity and to create an anastomotic leakage severity classification. Methods The TENTACLE—Esophagus is a multinational retrospective cohort study in which patients with anastomotic leakage after esophagectomy in the period 2011-2019 were included. Detailed data regarding casemix (e.g. age, sex, physical condition, comorbidity, tumor characteristics), surgical procedure (e.g. McKeown, Ivor Lewis, Orringer, anastomotic technique, omental wrap, pleural flap), leakage characteristics (e.g. contamination, drainage at leakage diagnosis, leak circumference) and treatment were collected. The primary outcome is 90-day mortality. Regression analysis will be used to analyze which leakage characteristics are associated with 90-day mortality and to compose an evidence-based anastomotic leakage severity score. The study protocol is accessible at www.tentaclestudy.com. Results Detailed data of 1407 patients with anastomotic leakage from 70 centers in 20 countries were collected. Anastomotic leakage occurred 0-43 days after surgery and 90-day mortality rate was 11.1%. The TENTACLE—Esophagus study data is currently being validated and it is awaiting full analysis. The results and the evidence based anastomotic leakage severity classification system will be ready for presentation at the ISDE meeting. Conclusion This is the largest study that investigates which factors contribute to anastomotic leakage severity after esophagectomy. The evidence-based anastomotic leakage severity classification system can be used by clinicians to grade severity of a given leak and might aid clinicians in choosing the most appropriate treatment.


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