Leak Pressure Research Articles

The figure-of-8 aortic valve suturing technique optimizes the effective orifice area of a small aortic annulus-an ex vivo study.

Surgical aortic valve replacement (SAVR) in small annuli carries an elevated risk for the patient-prosthesis mismatch. In this study, we systematically investigated the influence of different implantation techniques including annular enlargement (AE) on the functional result after SAVR in small annuli using a standardized ex vivo model. SAVR using the PERIMOUNT Magna Ease® (PME) 21 mm was performed in small porcine aortic roots using 4 implantation techniques: non-everting pledgeted (NE) suture, single interrupted (SI) suture, continuous suture (CS), figure-of-8 (F8) suture, as well as the PME 23 mm after AE using the Nunez method and the NE suture technique (PME23 AE). The effective orifice area (EOA), mean pressure gradient and leakage volume were evaluated using a mock circulation loop in accordance with ISO regulations. Experiments were conducted on 31 porcine aortic roots. PME21 using F8 and PME23 after AE achieved a significantly larger EOA than using NE. PME23 after AE showed a larger EOA than the PME21 using any suture technique, except the F8 [for stroke volume of 74 ml: PME21 NE: 1.68 (1.63-1.72) cm2, PME21 SI: 1.76 (1.68-1.81) cm2 (P = 0.17), PME21 CS: 1.76 (1.65-1.79) cm2 (P = 0.14), PME21 F8: 1.81 (1.70-1.85) cm2 (P = 0.005); PME23 AE: 1.83 (1.73-1.92) cm2 (P < 0.001)]. SI and CS did not result in larger EOA compared with the NE technique. PME21 using SI had a significantly larger leakage volume than using NE and there was no significant difference between other techniques [for stroke volume of 74 ml: PME21 NE: 3.51 (1.85-4.53) ml/stroke, PME21 SI: 6.00 (4.02-7.06) ml/stroke (P < 0.001), PME21 CS: 4.04 (3.60-4.49) ml/stroke (P = 0.10), PME21 F8: 3.16 (1.99-3.62) ml/stroke (P = 0.74), PME23 NE: 2.89 (2.45-4.72) ml/stroke (P = 0.51)]. The F8 technique with the PME21 achieved a similar EOA as the 1 size larger PME23 using NE after AE. These results suggest that the F8 technique may be an effective surgical modification to improve the haemodynamic result in a small annulus without additional AE.

Comparison of the third-generation streamlined liner of the pharynx airway (SLIPA-3G) with the laryngeal mask airway supreme for laparoscopic cholecystectomy: a randomized prospective study

BackgroundThe third-generation streamlined liner of the pharynx airway (SLIPA-3G) is a new-generation supraglottic airway device (SAD) that is non-cuffed and disposable, with a sealing pressure that varies dynamically with the airway pressure. This study compared the SLIPA-3G with the laryngeal mask airway supreme (LMAS) in patients undergoing laparoscopic cholecystectomy.MethodsTwo hundred and twenty patients scheduled for laparoscopic cholecystectomy were randomly allocated to either the SLIPA-3G group or the LMAS group. Data were collected on the patients’ hemodynamic parameters at different time points, ease of insertion, fiberoptic view, oropharyngeal leak pressure (OLP) at different time points and SAD-related complications.ResultsThe mean OLP immediately after device placement in the LMAS group was significantly higher than that of the SLIPA-3G group (31.34 ± 6.99 cmH2O vs.28.94 ± 6.01 cmH2O, P = 0.008, 95% CI 0.62–4.17). The OLPs of the two groups were not significantly different after the induction of a pneumoperitoneum until the end of surgery. The OLP increased gradually through the course of the operation in the SLIPA-3G group (P value = 0.035) but not in the LMAS group (P value = 0.945). There was no significant difference between the two groups in hemodynamic parameters, insertion time and success rate, fiberoptic view and complication rate.ConclusionsThe SLIPA-3G and LMAS were associated with comparable OLPs, hemodynamic parameters, ease of insertion, fiberoptic views and complication rates when used during laparoscopic cholecystectomy. The SLIPA-3G can be used as an effective alternative to the LMAS in patients undergoing laparoscopic surgeries.

Comparative study of Baska mask with proseal LMA in adult patients undergoing elective surgery under general anesthesia with controlled ventilation

Background and Aims:Several supraglottic airway devices (SGD) are available nowadays. But none has been found to be better than Proseal laryngeal mask (PLMA) in terms of oropharyngeal leak pressure (OLP). We aimed to compare OLP of newly introduced Baska® Mask with PLMA in patients undergoing elective surgical procedures under general anesthesia.Material and Methods:Totally, 80 consecutive adult patients of either sex requiring general anesthesia were randomized into two groups Group B (Baska mask, n = 40) or Group P (PLMA. n = 40). After standardized induction with propofol 2 − 2.5 mg/kg-1 and fentanyl 2 mgkg-1, and muscle relaxation with vecuronium 0.1 mgkg-1 one of the two devices was placed. OLP (primary outcome) was measured 5 minutes and 30 minutes post induction. The time needed to achieve effective airway, anatomical alignment of the device, number of attempts, leak fraction, and postoperative laryngopharyngeal morbidity were noted.Results:Both the devices could be inserted in first attempt in all the patients, but the time needed to achieve effective airway was significantly less in Group B (12.58 ± 1.81 sec vs 17.92 ± 2.45 sec, P < 0.001). The mean OLP was better in Group B at 5 min (37.6 ± 2.43 cm H2O vs 30.82 ± 3.96 cm H2O) and at 30 min (38.83 ± 1.72 cm H2O vs 30.82 ± 3.96 cm H2O; P < 0.001). Anatomical alignment of SGD with glottis (FOB grade 3 or 4 view) was significantly better in group B (34/40) as compared to group P (25/40) (p = 0.009). There was no difference in laryngopharyngeal morbidity in the two groups.Conclusion:Baska mask provided higher OLP, better alignment to the glottis and faster placement time as compared to PLMA.

Proposed Standards and Methods for Leak Testing Lithium-Ion Battery Packs Using Glycol-Based Coolant with Empirically Derived Rejection Limits

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Lithium-ion battery systems are an energy source for a variety of electric-vehicle applications due to their high energy density and low discharge rates. Battery packs, whether made of prismatic, cylindrical or pouch cells, are cooled by common automotive thermal management systems. The rapid detection of battery pack coolant-system leaks during production operations is essential for meeting necessary safety and service-life requirements. Industry standards for measuring leak rates for both glycol-based and refrigerant-based cooling systems, however, currently do not exist. This presentation will discuss how leaks in water-glycol cooling circuits can be detected reliably and quantitatively through detection of escaping test gas as an indicator of ethylene glycol leaks and how the test gas leak rates correlate to the liquid leakage of the cooling liquid. Influencing variables such as leakage channel diameter, pressure difference and viscosity are considered, and go/no-go leak rates are described.&lt;/div&gt;&lt;/div&gt;

Smart pressure management extension for EPANET: source code enhancement with a dynamic pressure reducing valve model

Abstract Applying pressure management reduces lost water and excessive hydraulic pressures in water distribution networks (WDNs). There are currently four different types of pressure management in the literature, i.e. fixed outlet, time modulated, flow modulated, and remote node modulated. The primary device used in pressure management is the pressure reducing valve (PRV) that dynamically controls the outlet pressure by moving up and down its main valve element. In this study, we firstly introduce the dynamic PRV model with four different pressure management types to the source code of EPANET v3.1 software and assess the effect of different valve opening schemes on pressure graphs and leakage quantities. The results showed that dynamic PRV significantly reduces lost water amounts and excessive hydraulic pressures in the WDN when valve opening is continuously adjusted. Our smart PM extension implemented into EPANET v3.1 software is publicly available in Zenodo repositories (https://zenodo.org/record/6243078).

Macroscopical contact pressure and microscopic leakage performance analysis of rubber seal considering thermal oxygen aging effect

Leakage performance of rubber seal is a key factor of spacecraft system, which is required long life. But the degradation law of the rubber seal performance in long service period is limited to qualitative analysis for its macro contact performance, and the quantitative research of rubber seal leakage performance is rarely involved considering thermal oxygen aging effect. Therefore, the thermal oxygen aging mathematical model is firstly established to predict the life of rubber material by aging tests. Secondly, the finite element model (FEM) of rubber seal performance analysis considering thermal oxygen aging effect is built to obtain the degradation law of its macroscopic contact performance with the increase of service time. Thirdly, the micro-leakage model of rubber seal considering thermal oxygen aging effect is established based on the material surface microstructure, contact pressure, and contact width, and the leakage rate of rubber seal is calculated by the model. Finally, the micro-leakage model of rubber seal is modified based on the experimental results, so the calculation accuracy of leakage rate is improved.

Adaptive DMA Design and Operation under Multiscenarios in Water Distribution Networks

Water distribution network (WDN) is a human-centered infrastructure that is indispensable for modern cities worldwide. In addition to optimizing the operation and management (O&amp;M) of WDNs under the current state, water utilities should be able to manage uncertain and risk conditions for improving their O&amp;M efficiency. Although the disintegration of large WDNs into permanent district metered areas (DMAs) is an O&amp;M innovation based on water leakage monitoring and pressure management, its network redundancy and reliability diminish under anomalous conditions. Therefore, this study proposed a design and operation procedure to obtain optimal, self-adaptive DMA configurations for various plausible abnormal scenarios. The proposed method is based on multiscenario simulation and optimization, comprising two phases: (1) design of optimal DMA layout for each scenario using the pressure uniformity index to optimize the placement of flow meters and gate valves, and (2) dynamic transformation of the base DMA configuration into an adaptive DMA layout adapting to abnormal conditions and optimization of the locations and statuses of the control valves. Moreover, we used a real-world WDN to demonstrate the effectiveness of the proposed approach, and the obtained results revealed the efficiency and appropriate performance of the adaptive DMA layouts for sustainable adaptation of WDNs under anomalous conditions.

Leakage simulation and acoustic characteristics based on acoustic logging by ultrasonic detection

The detection of casing leakage in oil and gas wells or water injection wells is an important element of wellbore integrity management. Ultrasonic technology is suitable to detect and identify the position of leakage in oil and gas well shafts, providing engineering guidance for subsequent treatment. In this paper, the finite element calculation model of casing leakage in oil and gas wells is established by using the computational fluid dynamics method, and the large eddy simulation model and Ffowcs Williams-Hawkings acoustic model are utilized to simulate the casing leakage condition. The acoustic pressure signals of each monitoring point on the inner axis of the pipeline are obtained, and the influences of the pipeline pressure difference, the leakage hole diameter and the pipeline fluid on the leakage acoustic field are analyzed. The simulation results indicate that the acoustic pressure level measured on the pipeline axis rises with the increase of pipeline pressure difference and leakage hole diameter. The size and variation rule of acoustic pressure level also vary with the type of pipeline fluid. Overall, the results obtained show that ultrasonic logging can accurately locate and detect tubing leakage, and they provide theoretical guidance for practical casing leakage detection, assisting with wellbore integrity management. Cited as: Li, J., Wan, J., Wang, T., Yuan, G., Jurado, M. J., He, Q. Leakage simulation and acoustic characteristics based on acoustic logging by ultrasonic detection. Advances in Geo-Energy Research, 2022, 6(3): 181-191. https://doi.org/10.46690/ager.2022.03.02

Clinical Performance Comparison of LMA Protector™ Cuff Pilot™ and LMA Supreme™ When Used in Anesthetized, Non-paralyzed Patients.

IntroductionThe advancement of supraglottic airways (SGAs) has eased airway management, especially for anesthetists. There were functional improvements implemented to the newer SGA. We aim to assess the clinical performance of laryngeal mask airway (LMA) Protector™ Cuff Pilot™ (Teleflex Inc., Wayne, Pennsylvania, USA) against LMA Supreme™ (Teleflex Inc., Wayne, Pennsylvania, USA), in terms of oropharyngeal leak pressure (OLP), successful insertion attempts, mean insertion time, ease of gastric tube insertion, laryngeal view, and incidence of sore throat among anesthetized, non-paralyzed patients undergoing general anesthesia.MethodsIn this prospective single-blinded study, 60 patients were randomized to use either LMA Protector™ Cuff Pilot™ or LMA Supreme™. Both groups received standard monitoring and induction regimes. Post-insertion, a bronchoscope was used to verify its position. A gastric tube was inserted and OLP was measured. Patients were assessed during the post-operative period for sore throats.ResultsLMA Protector™ Cuff Pilot™ was comparable to LMA Supreme™ in terms of mean OLP (30.72±8.60 vs 27.23±8.09 cmH2O, P = 0.114), first successful attempt (P = 0.312), mean insertion time (27.72±9.45 vs 24.37±6.46 seconds, P = 0.116), and grade 1 laryngeal view (51.7% vs 36.7%, P = 0.244). At first attempt, LMA Protector™ Cuff Pilot™ had a lower success rate of gastric tube insertion than LMA Supreme™ (55.17% vs 96.67%, P <0.001). The incidence of the blood-stained device and sore throat post-operatively were comparable between the two groups.ConclusionLMA Protector™ Cuff Pilot™ was comparable to LMA Supreme™ in terms of overall clinical performance, except for the first successful gastric tube insertion. Improvements should be made to the gastric channel for easier gastric tube insertion in the LMA Protector™ Cuff Pilot™.

Investigation of Internal Gas Leakage on the Gate Valve using Acoustic Signal

The gate valve is primarily used for starting/stopping the flow of fluids. It is suitable for most fluids such as water and chemicals as well as air, steam and gas in petrochemical and refinery plants that require high temperature and low pressure. The aim of this study is to define the frequency domain using AE signals, such as RMS and ASL, to determine the internal gas leakage. The conducted experiment employed a 4-inch diameter gate valve installed in the middle of the pipe length. To simulate industrial applications, the AE signals were observed at low-frequency (between 18.6 kHz to 19.5 kHz), with inlet pressures between 100 to 800 kPa and leakage rates between 0.5 percent to 2 percent. The frequency domain between 18.6 to 19.5 kHz and the inlet pressure of 100 to 800 kPa were displayed as the Root Mean Square (RMS) and Average Signal Limit (ASL). The pressure difference between the inlet and outlet influences the AE signal. The frequency spectrum can be correlated with the pressure leakage, thus providing leakage conditions. Therefore, the obtained results can be employed in industrial applications.

Abstract No.: ABS1770: Cuffed versus uncuffed endotracheal tubes in infants undergoing elective surgery in prone position:peritubal leak at standardised ventilator settings

Background & Aims:The purpose of this study was to compare peritubal leak in cuffed and uncuffed tubes in infants at standardised ventilatorsettings. Secondary objective was to see incidence of accidental extubation and postoperative respiratory complications such as stridor and sore throat.Methods:With ethics committee approval, a prospective,randomised,clinical study was conducted. Patients aged between birth to 1 year, American Society of Anesthesiologists ASA grade I,II and III, requiring general anaesthesia with orotracheal intubation in prone position during elective surgery were included and children with parents not giving consent,children with airway anomaly, laparoscopic surgery, and emergency surgery were excluded. Tracheal tube size was judged as adequate if the leak pressure was 20 cm H2O or less. Tube was exchanged to next larger size if the leak pressure was too high and tube size was exchanged to next smaller size, when cuff pressure exceeded 20 cm H2O.Results:60 infants were studied.In group 1 in which cuffed tube was used, there were no leaks,on the other hand, in group 2,17 out of 30 patients had peritubal leak and tube was exchanged to next larger size uncuffed tube, p value was <0.001. Moreover, the incidenceof accidental extubation, post extubation sore throat and stridor was more in uncuffed group, It was 2/6/6 in uncuffed group and 0/3/4 in cuffed group respectively. Tracheal tube exchange rate was also higher in uncuffed group.Conclusion:We found that in microcuff paediatric endotracheal tube, there is less peritubal leak; selection of cuffed tube with small internal diameter compared to uncuffed tubes implicates a higher chance for adequate fit of the tube at cricoid ring and due to this there is least chance of accidental extubation in the prone position.Peritubal leakGroup I (n=30)Group II (n=30)Total (n=60) No.%No.%No.%Absent30100.01343.34371.7Present00.01756.71728.3

Comparison of three purse-string suture techniques for prevention of anal leakage during surgery

To compare 3 anal purse-string suture techniques for resistance to leakage and to identify the suture technique requiring the fewest tissue bites to create a consistent leak-proof orifice closure. 18 large-breed canine cadavers. 3 purse-string suture techniques (3 bites with 0.5 cm between bites [technique A], 5 bites with 0.5 cm between bites [technique B], and 3 bites with 1.0 cm between bites [technique C]) were evaluated. Each technique involved 2-0 monofilament nylon suture that was placed in the cutaneous tissue around the anus and knotted with 6 square throws. Standardized 2.0-cm-diameter circular templates with the designated bite number and spacing indicated were used for suture placement. Leak-pressure testing was performed, and the pressure at which saline was first observed leaking from the anus was recorded. The median and interquartile (25th to 75th percentile) range (IQR) were compared among 3 techniques. Median leak pressure for technique A (101 mm Hg; IQR, 35 to 131.3 mm Hg) was significantly greater than that for technique C (19 mm Hg; IQR, 14.3 to 25.3 mm Hg). Median pressure did not differ between techniques A and B (50 mm Hg; IQR, 32.5 to 65 mm Hg) or between techniques B and C. Placement of an anal purse-string suture prevented leakage at physiologic colonic and rectal pressures, regardless of technique. Placement of 3 bites 0.5 cm apart (technique A) is recommended because it used the fewest number of bites and had the highest resistance to leakage.

Abstract No.: ABS1132: A Comparative study of Oropharyngeal leak pressure in LMA ProtectorTM with cuff pilot vs LMA SupremeTM in paralysed patients: A prospective randomised clinical study.

Background & Aims:Oropharyngeal leak pressure (OLP) is the pressure at which a gas leaks around the airway, higher leak pressures, betterseal. Our primary aim was to measure OLP and Secondary aims were to measure Insertion Time, Numbers of Attempts,Ease of Insertion, and Postoperative complications.Methods:The study was carried out in 62 adult patients of ASA I & II which were randomized into 2 groups Group S (LMA SupremeTM) and Group P (LMA ProtectorTM) (n = 31 each) based on a computer‑generated random sequence table.Respective LMA’s were inserted after general anaesthesia induction and OLP were measured at cuff pressure of 60 cmH2O in each group accordingly. Secondary Parameters such as insertion time, no of attempts of supraglottic airway devicesand gastric tube, ease of insertion were measured. Intraoperative haemodynamic parameters and postoperatively airwaymorbidity were also measured.Results:OLP were significantly higher (P<0.0001) for LMA Protectorâ„¢ compared to LMA Supremeâ„¢.The OLP in LMAProtectorâ„¢ group was 28.12 cmH2O (SD- 1.96) compared to 21.5 cmH2O (SD- 2.65) in LMA Supremeâ„¢ group. Insertiontime was significantly higher for the LMA Protectorâ„¢ (24.58 sec) compared to the LMA Supremeâ„¢ (16.67 sec) (P<0.0001). There were no statistically significant differences in ease of insertion, Numbers of Attempts, trauma, sorethroat, Dysphagia and Dysphonia.Conclusion:Oropharyngeal leak pressures were consistently higher (>5 cm H2O) for LMA Protectorâ„¢ compared to LMA Supremeâ„¢, Thus providing effective ventilation than LMA SupremeTM .

Telecoaching Improves Positive Pressure Ventilation Performance During Simulated Neonatal Resuscitations.

Introduction:Positive pressure ventilation (PPV) is a critical skill for neonatal resuscitation. We hypothesized that telecoaching would improve PPV performance in neonatal providers during simulated neonatal resuscitations.Setting:Level IV neonatal intensive care unit (NICU).Methods:This prospective crossover study included 14 experienced NICU nurses and respiratory therapists who performed PPV on a mannequin that recorded parameters of ventilation efficiency. Participants were randomized to practice independently (control) or with live feedback from a remote facilitator through audiovisual connection (intervention) and then switched to the opposite group. Participants' mask leak percentage, ventilation rates, and pressure delivery were analyzed.Results:The primary outcome of mask leak percentage was significantly increased in the telecoaching group (19% [interquartile range {IQR} 14–59.25] vs. 100% [IQR 88–100] leak, p = 0.0001). The secondary outcome of peak inspiratory pressure (PIP) delivery was also increased (median 27.6 [IQR 23.5–34.7] vs. 23.3 [IQR 19.1–32.8] cmH2O, p < 0.001). Differences in ventilation rates were not statistically significant (55 vs. 58 breaths/min, p = 0.51).Conclusion:Participants demonstrated better PPV performance during telecoaching with less mask leak. The intervention group also had higher measured peak inspiratory pressures. Telecoaching may be a feasible method to provide real-time feedback to health care providers during simulated neonatal resuscitations.Hypothesis:Neonatal providers who receive telecoaching during simulated resuscitations will perform PPV more effectively than those who do not receive telecoaching.

3: Comparison of the blockbustertm and air-q®supraglottic airway devices as a conduit to blind endotracheal intubation in paediatric patients: a randomised controlled trial.

Background and Aims:There is scarcity of literature recommending the use of supraglottic airway devices (SADs) as conduits for blind endotracheal intubation. This study was conducted to compare the efficacy of two laryngeal mask airways (BlockbusterTMSAD and air-Q® SAD) in acting as a conduit for blind endotracheal intubation in paediatric patients undergoing non-emergency surgeries under general anaesthesia.Methods:In this randomised controlled trial, 80 paediatric patients with American Society of Anesthesiologists (ASA) physical status I and II, aged between 6 months and 10 years and weighing between 5 to 30 kg, were randomly allocated to two groups in which the airway was secured either with BlockbusterTMSAD or air-Q® SAD followed by blind endotracheal intubation. The primary outcome was the percentage of successful blind endotracheal intubation in a single attempt. The secondary outcomes were oropharyngeal leak pressure (OLP), insertion time, manipulations, perioperative complications.Results:Success rate of intubation with BlockbusterTMSAD was significantly higher (p value = 0.03) as compared to with air-Q® SAD ( 77.5% vs 55%). OLP was also significantly higher (p value = 0.001) with BlockbusterTM SAD (25.74 ± 7.05) cm H2O as compared to air-Q® SAD (15.2 ± 5.58) cm H2O. Complications were comparable in the groups.Conclusion:We found that both BlockbusterTM and air-Q® SAD have good success rate; however, Blockbuster success rate was significantly higher. Hence we conclude that BlockbusterTM is a better SAD for use as a conduit to blind endotracheal intubation in paediatric patients. It can reliably be used as a ventilatory device as well because of better OLP.VariableBlockbusterAir-Q P Successful31 (77.5%)22 (55%)0.033Unsuccessful9 (22.5%)18 (45%)OLP (cm H2O)25.74±7.0515.20±5.580.001

Abstract No.: ABS1016: Comparison of clinical performance of I-GEL and LMA blockbuster in adult patient during general anaesthesia: a comparative randomised trial

Background & Aims:LMA BLOCKBUSTER is relatively newer second generation supraglottic device.There are various meta analysis comparing I-GEL and LMA SUPREME.However we conducted this study to compare clinical performance of I-GEL and LMA BLOCKBUSTER regarding oropharyngeal leak pressure and time for successful insertion.Methods:After getting approval from institutional ethical committee and getting CTRI registered, a total of 62 adult patients of American Society of Anesthesiologists physical status I/II between 20-60 years undergoing procedures for whichsupraglottic devices are used routinely, were included in this prospective randomised controlled trial and randomised into 2 groups by a computer generated random number sequence (Group I receiving I-GEL and Group L receiving LMABLOCKBUSTER) of 32 cases in each group. We compared oropharyngeal leak pressure and time for successful insertion onfirst attempt by visible end-tidal carbon dioxide (EtCO2) graph on the monitor.Results:Patients of both groups were comparable with each other in baseline demographic profile. Oropharyngeal leak pressure ofpatients of Group L (24.59±2.76 cmH2O) was found to be significantly higher as compared to Group I (20.60±2.33cmH2O) with p value <0.001. Whereas mean time of insertion of device was lesser in Group I (13.50±2.62 seconds) thanthat of Group L (14.09±2.01 seconds) yet this difference was not found to be statistically significant (p value=0.319)Conclusion:Both I-GEL and LMA BLOCKBUSTER can be used safely and effectively in terms of airway management in adult patientsundergoing general anaesthesia. Compared with commonly used supraglottic device I-GEL, LMA BLOCKBUSTER has higher oropharyngeal leak pressure and therefore provides high quality of airway sealing, but with lesser mean time of insertion for I-GEL.

Load condition analysis of pipe flange connection with gasket flat gasket and loose clamping rings

Purpose: This paper describes the study of the connection with loose fixing composite rings of pipe flanges. The elastic properties of the joint components - gasket, pressure flanges, rings and fixing bolts were determined experimentally. Design/methodology/approach: The criterion of joint tightness was formulated. The constructed model was used to determine the analytical dependence of the joint leakage pressure on the assembly torque of bolts tightening. The correctness of the model was confirmed by the agreement of the analytical results with the experimental results. Findings: Quantitative characteristics were determined for the selected type of joint. Practical implications: The formulated conclusions indicate the possibility of using the model to support the design process and to select the structural parameters of the joint meeting the operational requirements and safety criteria. Originality/value: Produced with recycled materials using.

Ex vivo comparison of different thoracoabdominal stapler sizes for typhlectomy in canine cadavers.

To determine the influence of staple size on leakage pressure of typhlectomy sites in canine cadavers. Randomized, experimental cadaveric study. Twenty-four fresh canine cadavers. Ileocecocolic segments were exteriorized following right paracostal laparotomy after euthanasia. Cecal base length and wall thickness were measured. Each cecum was randomly assigned to 1 of 3 groups (TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm). The cecal base was stapled and the cecum was removed. A 10cm segment including the stapled cecal excision site was tested for initial leak pressure. The mean ± standard deviation body weights across the groups were 18.7 ± 6.1kg, 16.2 ± 7.5kg, and 14.2 ± 5.5kg for the TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm groups, respectively (P=.48). There were no differences for mean cecal base length or wall thickness. Mean initial leak pressure (ILP) across groups was 182 ± 111 mmHg (TA 30 V3 2.5 mm), 112 ± 57 mmHg (TA 60 3.5 mm), and 77 ± 60 mmHg (TA 60 4.8 mm) (P=.78). Each stapler size that was evaluated resulted in a mean ILP in excess of typical intraluminal pressures under normal circumstances. There were no differences among groups. The results of this cadaveric study support the use of any of the stapler sizes evaluated in similarly sized dogs. A prospective study is needed to be able to correlate stapler size and clinical outcome.

Development of automated fumigation chamber for treatment of grapes with SO2 and CO2

AbstractThe export of grapes from one country to another is dependent on the grape's quality that should pass the strict phytosanitary requirements of the importing country. There is a requirement of fumigation of grapes with CO2 and SO2 at specified concentrations for a certain period besides the other pack‐house protocols and export standards. This study was focused to develop and establish an electronically controlled model fumigation chamber for the treatment of grapes in the grapes‐producing region. The gas injection and evacuation systems are electronically operated, and the fumigant concentration can be varied according to the requirement. Heaters of 2 kW are fitted inside the chamber to maintain the treatment temperature above 16°C for grapes fumigation. The fumigation chamber was found leak‐proof during pressurized helium leak testing. The CO2 and SO2 gas concentrations can be maintained between 600 and 60,000 ± 100 ppmv and 10 and 10,000 ± 2 ppmv, respectively, for 1–90 min (1% is equivalent to 10,000 ppmv). The fumigation of grapes with 6% CO2 for 30 min followed by fumigation with 1% SO2 for 30 min ensured 100% mortality of the adult fruit fly (Drosophilla melanogaster). This chamber may also be used for the fumigation treatment of other fruits, vegetables, nuts, and so on, as per the time and concentration of gases required for the 100% mortality of target pest. Nevertheless, the protocol for such treatments should be developed for other fruits, and the effect of the gases on the quality of the products should be studied.Practical ApplicationsThe developed automated fumigation chamber for treatment of grapes with CO2 and SO2 is an effective measure for disinfesting the grapes from invasive pests like Drosophilla suzukii, spiders, and so on. This would help in overcoming phytosanitary measures put in place by many grapes importing countries like New Zealand, Australia, and so on. These countries offer huge market potential for export of Indian grapes, and if the trade barriers are overcome, it would lead to earning huge foreign exchange. Furthermore, the developed automated fumigation chamber can be used as an integral part of horticultural pack houses both for domestic as well as international trade as it would eliminate most of the adult field pests at preliminary stages before pack‐house operation.

Identifying two-point leakages in parallel pipelines based on flow parameter analysis

Parallel pipelines are widely used to transport energy resources. Leakages usually can occur in pipelines due to aging, corrosion, metal failure, etc. When an accident happened, not only the energy company would take the financial loss, but also it would cause pollution and safety issues to the local environment. Therefore, an efficient way to identify leakages in parallel pipelines is necessary to be proposed. In this study, ANSYS was used to simulate different leak scenarios in parallel pipelines. Fluid and pipe parameters were used to simulate different leak scenarios. In each leak scenario, there were different pressure drops along the leak pipeline based on leak locations and different flow rates. After determining there is more than a leak in pipelines, the relationship among pressure drops, leak locations, and flow rates can be used to build a mathematical model for detecting leaks. During the pipeline operations, the pressure drops were affected by leak locations and flow rates. Therefore, applying flow parameters in real leak scenarios to the mathematical model that is built from the parameters in the reality will identify the leak locations. In addition, lab experiments were applied to verify the validity of the simulations. The deviations between the experiments and simulations are less than 4%. The pressure drops through the leak pipe in the experiments and simulation vary from 1,955 to 2,898 Pa and 1,992 to 2,803 Pa, respectively. This research investigated a method to identify two-point leakages in parallel pipelines based on flow parameter analysis.