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The MT-II is a small spherical tokamak that is currently under construction at the Pakistan Tokamak Plasma Research Institute. Wall conditioning of the MT-II vacuum vessel (VV) is an essential step to achieve a good quality vacuum for plasma experiments. This study presents an overview of the wall-conditioning techniques implemented on the MT-II VV, including baking and glow discharge cleaning (GDC). Prior to wall conditioning, the system is checked via a helium leak test machine and residual gas analyzer (RGA) to identify and remove leaks. The VV walls are baked at ~180 °C to get rapid desorption of water vapors and other impurities. After the baking process, the partial pressure of most of the carbon- and oxygen-containing impurities is reduced. In particular, the partial pressure of water vapors is reduced by 93%. Consequently, the total leak and outgassing rate is significantly reduced. To further improve the vacuum condition in the vessel, hydrogen GDC is carried out. The fill hydrogen pressure and anode voltage are optimized to get a stable glow discharge. The RGA scan shows that GDC reduces the partial pressure of H2O, O2, and CO2 by 57%, 63%, and 51%, respectively. The results signify that baking and GDC are effective techniques for wall conditioning of the MT-II VV. [ABSTRACT FROM AUTHOR]

Pressure and flow rate are the most important hydraulic parameters in natural gas pipeline flow, and leak rate is the most crucial parameter after a leak accident occurs. The study of these parameters is vital to the safey of natural gas pipelines and risk assessment after accidents. In this research, based on the conservation laws universally applicable to the motion of objects, we establish the fundamental control equation group for natural gas flow. Then, for both normal and leak conditions of pipelines, we use the characteristic line method to derive the corresponding difference equations for the fundamental control equations, thereby providing calculation methods for pressure and flow rate. Finally, we investigate the calculation method of natural gas pipeline leak rate under different leak aperture sizes, and validate the accuracy of this method through simulation examples. [ABSTRACT FROM AUTHOR]

The sample tubes on board NASA's Perseverance rover are designed to contain rocks, regolith, and atmospheric gases and are hermetically sealed on the surface of Mars to minimize sample loss, alteration, and contamination. Following a robust testing program during mission development, it was determined that the helium (He) leak rates of flight-like sample tubes sealed under a range of conditions were typically no greater than ∼10−10 standard cubic centimeters per second (scc/s); leak rates below this value could not be measured since this is the detection limit of commercially available He leak detectors. This limit was adequate to meet mission requirements. However, some scientific objectives could be compromised by sample tube leak rates even below 10−10 scc/s, thus motivating a more sensitive technique for establishing leak rates. This study investigated He leak rates on six flight-like sample tubes using a static mode mass spectrometer. Room temperature He leak rates of the six sample tubes ranged from ∼8.8 × 10−17 to ∼4.6 × 10−14 scc/s. One sample tube was analyzed at eight different temperatures, ranging from -51°C to +42°C, and yielded He leak rates correlated with temperature that varied from ∼1.7 × 10−15 to ∼1.4 × 10−13 scc/s, respectively. Our results confirm and extend previous findings demonstrating that the Mars 2020 sample tube seals are likely to be very leak-tight, with leak rates <10−13 scc/s. These leak rates are sufficiently low that the impact of gas egress or ingress is expected to be negligible. [ABSTRACT FROM AUTHOR]

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In this paper, the diffusion law of helium gas inside composite materials was obtained through numerical research and an experimental approach. The influence of fiber and the fiber–resin interface on permeability was discussed in the actual numerical model. It was found that the leak rate and the mass concentration at the fiber–resin interface were higher than those in the resin, and the leak rate symmetrically distributed along the horizontal central line. Meanwhile, a homogenized model for the leak rate simulation in carbon fiber composite components was established, and its accuracy was verified through the experiment and the actual numerical model. The simulated result and the test data demonstrated that the leak rate increased with the pressure and decreased with the thickness of the specimen. [ABSTRACT FROM AUTHOR]

This paper summarizes the results of a pilot experimental program intended to develop a robust data for global airflow through cracked concrete, with comparisons against a traditionally used prediction method. Current models for predicting airflow through concrete based on Poiseuille flow poorly translate to large-scale specimens and real-world conditions without calibration. This paper presents a novel testing apparatus that will be used to identify key variables affecting flow rate and develop numerical prediction methods for industrial application. [ABSTRACT FROM AUTHOR]

Minimally invasive surgery (MIS) has improved surgical access to the foregut. While the benefits of MIS versus open surgery are well accepted, the relative benefits of laparoscopic versus robotic approaches continue to be debated. Procedure-specific comparisons are difficult to obtain for Heller myotomy, due to the relative rarity of the procedure in most practices. A retrospective review of prospectively collected perioperative data of a single surgical practice from 2001 to 2019 was conducted for the rate of perforation during Heller myotomy laparoscopically compared to robotically. From 2001 through February 2012, a laparoscopic approach was employed and from October 2008 to 2019, a robotic approach was employed. All perforations were recorded, as well as secondary outcomes of perforation location (gastric or esophageal), postoperative imaging for evidence of leak, length of stay, and complications. Chi-square and simple t test were employed for data analysis. During the 11 years of laparoscopic Heller myotomy, 14 cases resulted in 7 instances of perforation (50%). During the 11 years of robotic Heller myotomy, 45 cases resulted in 11 instances of perforation (24%) (p value = 0.06). All perforations in both groups were tiny, recognized, and repaired immediately. The length of stay (LOS) was longer in the laparoscopic perforation group (3.4 days) compared to the laparoscopic non-perforation group (1.2 days) (p value = 0.06). LOS for robotic was not significantly longer in the perforation group (2.8 days) compared to the robotic non-perforation group (1.5 days) (p value = 0.18). First time Heller myotomies showed a higher rate of perforation with laparoscopic (50%) vs robotic (14%) (p value = 0.009) approach. In subgroup analysis of revisional procedures, all ten were performed robotically (p value < 0.001) with a 60% perforation rate (p value = 0.001) and one associated, radiographically confirmed leak. Primary laparoscopic Heller myotomy related to more than four times the frequency of perforation than did primary robotic myotomy. We propose that the robotic platform provided the surgeon with superior ability to avoid perforation. Interestingly, the robotic group in this study dealt with more complex redo cases. In fact, reoperation in the area of the hiatus was a separate risk factor for perforation during robotic Heller myotomy. We recommend further prospective trials be done to better evaluate the benefits of robotic platform in regard to revisional foregut surgery. [ABSTRACT FROM AUTHOR]

Aim: After total mesorectal excision (TME) for low rectal cancer, current guideline recommendations for sphincter‐saving surgery are to perform a side‐to‐end manual coloanal anastomosis (CAA) (or with J‐pouch) with a temporary stoma. Our study aimed to evaluate if delayed pull‐through coloanal anastomosis (DCAA) without a temporary stoma could represent a safe alternative in low rectal cancer. Method: From 2003 to 2020, 223 consecutive patients with low rectal cancer undergoing TME were compared: CAA and diverting stoma (n = 190) versus DCAA without stoma (n = 33). Results: Overall 3‐month and severe (Dindo ≥ IIIb) morbidity rates were similar in CAA versus DCAA groups: 34% (65/190) vs. 36% (12/33) and 2.6% (5/190) vs. 3% (1/33), respectively. In the DCAA group, only one patient (3%) underwent reoperation (Hartmann's procedure) at day 3 due to colon necrosis. The anastomotic leakage rate (both clinical and radiological) was significantly higher after CAA than DCAA: 28% (53/190) vs. 3% (1/33; p = 0.00138). Failure of the procedure (with return to stoma) was observed in 8% (15/190) vs. 6% (2/33) of patients after CAA and DCAA respectively (not significant). Conclusion: Our comparative study suggested that in patients with low rectal cancer, DCAA without a temporary stoma could represent an interesting alternative to the actual recommended CAA with a temporary ileostomy. DCAA could offer two major advantages over CAA: a significantly lower rate of anastomotic leakage and absence of a temporary stoma and its potential complications (rehospitalization, dehydration, wound hernia after stoma closure). [ABSTRACT FROM AUTHOR]

In carbon-intensive industries like oil and gas production, ESG (Environmental, Social, Governance) reports provide investors with information about carbon intensity performance and there is link between environmental and financial performance. In Canada, ESG reporting is not obligatory, and multiple frameworks are used making performance comparisons across producers challenging. Additionally, methane emissions from the oil and gas industry are underestimated in Canada which also suggests systemic under-reporting of emissions in this key area of carbon intensity. Here we investigate 2019 methane emission intensity gaps for 70 of Canada's largest oil and gas producers, between 1) provincial regulatory submissions, 2) assumed contributions to the federal inventory estimates, 3) a mobile ground laboratory measurement-based inventory, 4) and producer self-published ESG. We de-aggregated existing methane inventory estimates and measurements for Canada's largest producing province, Alberta, and found a greater than 1000-fold variation in methane intensities within the cohort. We also found surprisingly broad agreement in assumed methane emission intensities between (2) and (3), suggesting they capture the same signals. Regulatory submissions captured only a small amount of the total methane inventory and we also observed a low bias in regulatory reporting. In conclusion, we believe that changes to required and voluntary reporting, and associated systems management frameworks are needed to differentiate oil and gas producers and preserve market access based on carbon intensity.

Study the effect of the insulating layers on the liquid pipeline leakages and determining the leakage profile calculation model is critical and basic for the leakage-associated fire and explosion risk assessments for the chemical process industry. This research carried out a series of experiments, with an attempt to explore the leakage process of insulated pipeline. The experiments display that the leakage is dynamic, which is divided into three stages: initial, transitional and stable period. During the stable period, both the leak rate and pressure of insulated pipeline responding to work condition are different from those of naked pipeline. Then a fundamental formula is derived from the experimental data which is applicable for leakage calculation with insulating layers. Besides, sensitive factors that affect the leak volume are analyzed, among which the thickness of insulating layer is the most influential one. The research has designed a CFD model to reveal the dynamic leakage process in insulating layers and verify the effectiveness and accuracy of experiments. The result of this paper could improve risk assessment preciseness of liquid pipeline leakage. [ABSTRACT FROM AUTHOR]

With the increasing demands for liquefied natural gas (LNG), more and more LNG terminals are being constructed, and the risk of leakage during LNG off-loading processes has been given increasing amounts of attention. In the case of leakage accident during unloading, the control system is still running when the emergency stop condition is not reached. The adjustment of the control system to unloading parameters will affect the size of the leakage amount. However, the consequences of hazardous material leakage accidents predicted by correlation models depend on the amount of leakage. For precisely calculating the leakage amount and analyzing the leakage consequence, an HYSYS model and a flame acceleration simulator (FLACS) model were presented. This paper consists of two main parts: 1) an HYSYS model to calculate the spill flow rate according to various operating conditions that are with and without basic process control system (BPCS) intervention and 2) a FLACS model that estimates the consequences of vapor explosions and pool fires. This paper presents the conventional estimation method and compares it with a new method that estimates the risk according to spill flow rate, meteorological conditions, and substrate type (solid or grated) on pool spreading and vapor cloud dispersion. Using six scenarios, simulations are used to demonstrate that the HYSYS-FLACS model calculates the equivalent stoichiometric clouds (Q9) and pooling areas as being much larger than those calculated by the conventional model. During an emergency, the HYSYS-FLACS model can be used to estimate the consequences of an unplanned LNG release.

Background: Obesity is becoming a worldwide health problem. Recently, bariatric surgeries are developing to combat with thisproblem. However, these surgical methods themselves have risks.Objectives: The present study investigated the preventive effect of routine leak test of both gastrojejunal and jejunojejunal anastomosesimmediately after laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery against post-operative leak by inexperienced surgeons.Methods: In a prospective interventional study, this research enrolled 52 morbid obese patients with LRYGB from September 2014to October 2016. After anastomoses, methylene blue and air leak tests were performed and the section line and both anastomosissites for patency and inspected for air and dye leaks were examined.Results: Mean body mass index of patients was 48.84±6.8 kg/m2. Twelve patients had positive leak test and the anastomoses werereinforced by additional sutures. All patients were discharged with no leak and no patient had leak during the routine follow-up period.Conclusions: Intraoperative leak test of both gastrojejunal and jejunojejunal anastomoses is a valuable test in the assessment ofleak during LRYGB surgery, especially in unskilled surgeons.

Background: Exposure to inhalation of anticancer drugs is frequent in anticancer drug handling. Using an activated carbon mask with the ability to remove particulates and vapors of anticancer drugs may be effective. Mask fitting performance is important, because low fitting performance leads to inhalation via bypassing the mask filter (leak). This study evaluated the leak rate of multiple-shaped masks. Methods: Activated carbon and nonactivated carbon masks of the pleated-type (like surgical mask) and cup-type were used. Four pharmacists wore the masks and a fitting tester was employed. The particle reduction rate of particles in ambient air was calculated using: particle count (outside - inside)/outside × 100 (%). Leak rate was calculated as the difference in the particle reduction rate due to the presence or the absence of a seal in the mask surroundings. Results: Reduction rates of the pleated-type nonactivated carbon mask and the pleated-type activated carbon mask were 14.8% and 34.8% (mean). These values significantly increased to 85.6% and 83.3% upon sealing the mask surroundings. Particle reduction rates of the cup-type nonactivated carbon mask and activated carbon mask were 99.3% and 33.6%. When mask surroundings were sealed, these values were 99.6% and 39.2%. Leak rates of pleated-type nonactivated carbon mask, pleated-type activated carbon mask, cup-type nonactivated carbon mask, and cup-type activated carbon mask were 70.8%, 48.5%, 0.3%, and 5.6%, respectively. Conclusion: A difference was found in the leak rate between masks used in anticancer drug handling. Based on the low leak rate, the cup-type activated carbon mask was thought to be effective. [ABSTRACT FROM AUTHOR]

Aims: Anastomotic leakage is one of the most worrisome complications in colorectal surgery. An expert meeting was organized to discuss and find a consensus on various aspects of the surgical management of colorectal disease with a possible impact on anastomotic leakage. Methods: A three-step Delphi-method was used to find consensus recommendations. Results: Strong consensus was achieved for the use of mechanical bowel preparation and oral antibiotics prior to colorectal resections, the abundance of non-selective NSAIDs, the preoperative treatment of severe iron deficiency anemia, and for attempting to improve the patients' general performance in the case of frailty. Concerning technical aspects of rectal resection, there was a strong consensus in regard to routinely mobilizing the splenic flexure, to dividing the inferior mesenteric vein, and to using air leak tests to check anastomotic integrity. There was also a strong consensus on not to oversew the stapled anastomoses routinely, to use protective ileostomies for low rectal and intersphincteric, but not for high-rectal anastomoses. Furthermore, a consensus was reached in regard to using CT-scans with rectal contrast enema to evaluate suspected anastomotic leakage as well as measuring C-reactive protein routinely to monitor the postoperative course after colorectal resections. No consensus was found concerning the indication and technique for testing bowel perfusion, the routine use of endoscopy to check the integrity of the anastomosis, the placement of transanal drains for rectal anastomoses and the management of anastomotic leakage with peritonitis. Conclusion: Consensus could be found for several practice details in the perioperative management in colorectal surgery that might have an influence on anastomotic leakage. [ABSTRACT FROM AUTHOR]

• The leak rate prediction models of LBB were established for SFR. • The leak rate prediction program (LAPIS) for sodium pipelines was developed. • The effects of crack morphology parameters on leak rate were studied. The Leak Before Break (LBB) technology plays a vital role in the safety evaluation of Sodium-cooled Fast Reactor (SFR). In this study, the leak rate considered in LBB assessment of SFR was predicted and analyzed. Based on the models of fluid resistance in cracks, two-dimensional numerical simulation for leakage process of uniform cross-section axial cracks were conducted with Computational Fluid Dynamics (CFD) to obtain recommended values of crack empirical parameters, including entrance resistance coefficient, effective parameters and friction factors. With consideration of the complex crack morphologies, the leak rate prediction models with a wide range of parameters were established for liquid sodium, and corresponding computation code (LAPIS) was developed. The proposed models were verified and validated by seepage model, numerical results and experimental data with deviations within 1%, 35% and 10%, respectively. The effects of the crack morphology and thermal-hydraulic parameters on the leak rate for tight and wide cracks were studied with the LAPIS. The leak rate increases with Crack Opening Displacement (COD), crack length, ratio of entrance to exit area, entrance resistance coefficient, stagnation pressure and decreases with temperature. This work could provide theoretical and technical support for the study of leak rate considered in LBB assessment of SFR. [ABSTRACT FROM AUTHOR]

Introduction: Staple line reinforcement (SLR) is a commonly used technique during laparoscopic sleeve gastrectomy (SG) for severe obesity. There remains controversy over the potential benefit or risk associated with SLR. There are currently no consensus recommendations about SLR use. Its use is surgeon-dependent and remains controversial. Study Aim: To determine the impact of staple line reinforcement on staple line leak and bleeding rates after sleeve gastrectomy. Methods: Using the Metabolic and Bariatric Surgery Quality Improvement Program Participant User File (MBSQIP-PUF) database, we identified patients who had a SG in 2015 and 2016. SLR utilization status was used to create two cohorts. An unmatched cohort analysis was performed, and the outcomes were compared. A propensity score and case–control matched cohort analysis were then performed, and the outcomes were compared. Statistical analysis was performed with SPSS and SAS. Results: Of the 189,173 SG cases identified, SLR utilization was noted in 127,521 (67.4%). In the unmatched analysis, bleeding and reoperation were significantly higher in the cohort without SLR utilization. In both propensity score and case–control matched analysis, bleeding and reoperation remained significantly higher in the cohort without SLR utilization. There was no difference in mortality and staple line leak rates between the cohorts. Conclusions: SLR significantly reduces bleeding and reoperation rates following SG and has no deleterious impact on staple line leak rate. While further prospective studies factoring in the SLR method and staple characteristics are needed, this large database analysis supports the use of routine SLR during SG to reduce the risk of perioperative bleeding and reoperation. [ABSTRACT FROM AUTHOR]

Natural gas production in the United States has increased rapidly over the past decade, along with concerns about methane (CH4) fugitive emissions and its climate impacts. Quantification of CH4 emissions from oil and natural gas (O&NG) operations is important for establishing scientifically sound policies for mitigating greenhouse gases. We use the aircraft mass balance approach for three flight experiments in August and September 2015 to estimate CH4 emissions from O&NG operations over the southwestern Marcellus Shale. We estimate a mean CH4 emission rate as 21.2 kg/s with 28% coming from O&NG operations. The mean CH4 emission rate from O&NG operations was estimated to be 1.1% of total NG production. The individual best‐estimate emission rates from the three flight experiments ranged from 0.78 to 1.5%, with overall limits of 0% and 3.5%. These emission rates are at the low end of other top‐down studies, but consistent with the few observational studies in the Marcellus Shale region as well as the U.S. Environmental Protection Agency CH4 inventory. A substantial source of CH4 (~70% of observed CH4 emissions) was found to contain little ethane, possibly due to coalbed CH4 emitted either directly from coal mines or from wells drilled through coalbed layers in O&NG operations. Recent regulations requiring capture of gas from the completion‐venting step of hydraulic fracturing appear to have reduced the atmospheric release of CH4. Our study suggests that for a 20‐year time scale, energy derived from the combustion of natural gas extracted from this region likely exerts a net climate benefit compared to coal. Plain Language Summary: In this study methane (CH4) emission rates were estimated for the southwest Marcellus Shale based on airborne observations. A mean emission rate of ~21 kg CH4/s was observed from a 4,200‐km2 study area. A significant portion (~70%) of the emitted CH4 was found to originate likely from coalbeds. Our mean estimated emission rate of 1.1% of total natural gas production indicates a climate benefit of natural gas combustion compared to coal, but the full range includes values above the 2.4% break‐even point for the CH4 global warming potential over a 20‐year time horizon. Key Points: A CH4 emission rate of ~21 kg/s from a 4200 km2 area of the southwestern Marcellus in 2015 with the bulk of the CH4 coming from coalbedsWe estimate a mean CH4 emission rate of 1.1% of total natural gas production with a lower limit of 0% and an upper limit of 3.5%The mean emission rate indicates a climate impact of CH4 combustion below that of coal, but the full range includes values above this point [ABSTRACT FROM AUTHOR]

The accurate estimation of leak rate through cracks is crucial in applying the leak before break (LBB) concept to pipeline design in nuclear power plants. Because of its importance, several programs were developed based on the several proposed flow models, and used in nuclear power industries. As the flow models were developed for a homogeneous pipe material, however, some difficulties were encountered in estimating leak rates for bimaterial pipes. In this paper, a flow model is proposed to estimate leak rate in bimaterial pipes based on the modified Henry–Fauske flow model. In the new flow model, different crack morphology parameters can be considered in two parts of a flow path. In addition, based on the proposed flow model, a program was developed to estimate leak rate for a crack with linearly varying cross-sectional area. Using the program, leak rates were calculated for through-thickness cracks with constant or linearly varying cross-sectional areas in a bimaterial pipe. The leak rate results were then compared and discussed in comparison with the results for a homogeneous pipe. The effects of the crack morphology parameters and the variation in cross-sectional area on the leak rate were examined and discussed.

The leak before break (LBB) concept is widely used in designing pipe lines in nuclear power plants. According to the concept, the amount of leaking liquid from a pipe should be more than the minimum detectable leak rate of a leak detection system before catastrophic failure occurs. Therefore, accurate estimation of the leak rate is important to evaluate the validity of the LBB concept in pipe line design. In this paper, a program was developed to estimate the leak rate through circumferential cracks in pipes in nuclear power plants using the Henry–Fauske flow model and modified Henry–Fauske flow model. By using the developed program, the leak rate was calculated for a circumferential crack in a sample pipe, and the effect of the flow model on the leak rate was examined. Treating the crack morphology parameters as random variables, the statistical behavior of the leak rate was also examined. As a result, it was found that the crack morphology parameters have a strong effect on the leak rate and the statistical behavior of the leak rate can be simulated using normally distributed crack morphology parameters.

A radon chamber is a standard apparatus for experimental research of radon that can simulate ambient conditions such as atmosphere, ground surface and subsurface, and the dynamic stabilization technology of radon concentration in a radon chamber is the core technology of radon chamber research. In this paper, an attenuation method was proposed based on a radon leakage attenuation model for calculation of leak rate, a kernel parameter of the stabilization technology of radon concentration in a closed radon chamber, as well as a bench method based on a radon replenishment model for calculation of the effective generation rate at radon source, another kernel parameter of stabilization technology. In this study, the present methods were applied to parameter calculation in an HD-6-type small/medium-sized radon chamber, achieving an excellent application effect. [ABSTRACT FROM AUTHOR]

The new type Fe-Ni-Cr-Ti alloy mainly used in pressure sensors. Follow this new type pressure sensor’s characteristics of ultra-thin wall, in order to get the accuracy level of leak rate below 1×10-7Pa·L/S and the fitting precision reach 0.01%FS, the raw material bar with fine and uniform microstructure and consistency of performance plays a key role. This paper research the influence on microstructure of the heat treatment process with different solution temperature and different solution time. The results shows that the grain size of the raw material bar quenched at 980°C×60 minutes before a certain cold deformation is 5 or smaller, which achieve the desired goal of fine and uniform microstructure,it is beneficial to prepare sensors with excellent vibration characteristics,and satisfy the element’s performance index of leak rate fitting precision. [ABSTRACT FROM AUTHOR]

This paper investigates the fluidic leak rate through sealing contact surfaces by comparison between model calculation and experiment measurement. The focus is on an experimental device designed to measure the leak rate of the static seals with a simpler structure, smaller errors, stronger stability, and more functions. Using the device, experiments were carried out to four test pieces with different surface characteristics, whose leak rates were measured separately. Compared with the calculation results obtained from the fractal surface leak rate prediction model, the correctness and the application range of the model were verified, and the effects of different surface topographies and material properties of the four test pieces on the leak rate were analyzed as well. The experimental device was also used to perform single-factor comparison experiments, which were then combined with the theoretical prediction model to analyze the effects of the sealing surface contact load, fluid pressure, and surface apparent size on the leak rate, so that theoretical support and experimental evidence for selecting the parameters of sealing device was provided. [ABSTRACT FROM AUTHOR]

Abstract: The surface roughness or solitary grooves decides about success or failure of diffusion bonding and vacuum tightness of the parts to be welded. Since surfaces have to be mated at atomic level to enable diffusion of atoms across bonding planes, also single deep scratches must be avoided to achieve vacuum tightness. Up to now there are no criteria which grooves can be tolerated. In fact, personal experience of the operator is essential to evaluate the surface before diffusion bonding. In this paper different load on top of a spike made of hard metal and sliding across the surface of austenitic stainless steel sheets of 1.4301 are employed to prepare grooves of different depth. A scanning electron microscope is used to visualize the dimension of the grooves. By white light interferometry, the depths according the load of the spice is evaluated. Diffusion bonding is performed at T = 1075 °C, t = 4 h, p = 12 MPa as well as with additional short peak loads. It turns out that the depth of grooves corresponds very well with the degree of leakage rate. Hence, by measuring the depth of grooves, prediction of leak rate can be predicted. [ABSTRACT FROM AUTHOR]