Seal Pressure Research Articles

Effect of Head and Neck Positions on Oropharyngeal Seal Pressure with Baska Mask Versus I- Gel: A Prospective Randomized Interventional Study

Effect of Head and Neck Positions on Oropharyngeal Seal Pressure with Baska Mask Versus I- Gel: A Prospective Randomized Interventional Study

Numerical Prediction of Refrigerant Oil Two-Phase Flow from Scroll Compressor Discharge to the Suction Side via Back Pressure Chamber

Oil lubricates the contact between the orbiting and stationary scroll in the refrigerant scroll compressor, while the sealing between the scrolls is achieved through the refrigerant vapour pressure in the sealed back pressure chamber. The back pressure should be adjusted using the refrigerant oil two-phase flow from the oil separator at the compressor discharge to the back pressure chamber and the refrigerant oil flow from the back pressure chamber to the compressor suction side. Both of the flows are conducted through connecting tubes with corresponding high-pressure and low-pressure nozzles with small diameters. Models for predicting the refrigerant oil critical and subcritical flows through the nozzles were developed and applied in enable the prediction of the back pressure. The models are original, because the slip between the oil and the refrigerant as well as the refrigerant solubility in the oil are taken into account. The critical flow model is validated against the experimental data that are available in the literature. The back pressure is predicted by equating the mass flow rates of refrigerant and oil two-phase mixtures through the high- and low-pressure nozzles. The results show that the critical flow takes place through the high-pressure nozzle, while the subcritical flow through the low-pressure nozzle can also exist in cases with a small pressure difference between the back pressure chamber and the compressor suction side. The refrigerant solubility in the oil has a small influence on the critical and subcritical refrigerant oil mixture mass flow rates, while the influence on the back pressure is more pronounced.

Guest Editorial: The Engineer of the Future

Recently, at the SPE Annual Technical Conference and Exhibition, I was asked a question about the ‘engineer of the future.’ As we take a pause to turn the page to next year, I believe now is a prescient time to contemplate what’s next for petroleum engineering. Throughout my career, I’ve been able to witness great change in our industry as the shale revolution took hold making horizontal drilling and hydraulic fracturing commonplace, diagnostic and modeling tools improved in access and cost, and data became more timely and readily available. This led to a tremendous period of US energy supply growth and decades-long productivity improvements. Looking forward, I believe there are three trends that engineers should consider: 1) applying “new” tools to solve “old” problems, 2) connecting the dots via hybrid engineering, and 3) organizing, directing, and inserting data predictions into their workflow. These are not only my views but also the views of Devon’s talented engineers. Old problems will meet new solutions. The past decade has been dominated by unconventional horizontal development that was first pioneered in the Barnett Shale for natural gas and shortly thereafter transitioned into oil-focused development in the Bakken and Eagle Ford. Today, the Permian Basin continues to grow in total supply as the stacked pay is developed. Engineers should take stock of the tool set we have acquired during this era with a mindset to deploy these methodologies to tier II unconventional extensions, previously developed or bypassed conventional formations, offshore and international opportunities, enhanced recovery projects such as EOR and refracturing, and new energy opportunities like geothermal. To make these future opportunities competitive and meet the global demand for energy, we will likely need a combination of price, technology, and cost improvements. Engineers are critical to the latter two. To better illustrate these points let’s utilize examples. Drilling rig specification improvements have been coupled with material science and design improvements in bottomhole assemblies. The outcome is improved topdrives and mud pressure systems to power more durable and efficient downhole motors and bits, thus reducing failures, enhancing the efficiency of a rig’s daily footage, and enabling longer laterals. If we pivot to the completion space, our diagnostics for frac geometry have gone from limited and costly to a menu of options that provide fit-for-purpose diagnostics and costs. Devon deployed its first permanent fiber diagnostics in unconventional shale in 2012. Today, the same system is readily available but for a much lower cost. However, more frequently Devon has supplemented this tool with dip-in fiber and a proprietary methodology called sealed wellbore pressure monitoring to gather more frequent data points for frac geometry and design. As our team conducted, in cooperation with the US Department of Energy (DOE), a novel Eagle Ford project capturing horizontal core and completion diagnostics, we recognized that our designs have tremendously improved in efficiency but still have potential to capture more of the resource via initial and secondary fracturing efforts.

Research on internal flow field analysis and power loss modeling of the expansion seal ring

Expansion seal rings are widely used in automobile transmission systems, and their sealing performance plays a vital role in the pressure stability and transmission efficiency of the transmission system. However, investigations into revealing the internal flow mechanism of the expansion seal ring and predicting the power loss of the expansion seal ring are still insufficient. In this study, a two-way fluid–structure interaction model consisting of the shaft, oil sleeve, and expansion seal ring was established. The flow and structural physical fields under a series of operating conditions were simulated, and the effects of oil temperature, rotational speed, and seal pressure differential on leakage rate, deformation, power loss, and contact pressure were analyzed. Further, a power loss prediction model was developed by multiple linear regression method. The results demonstrate that in the internal flow field, the oil flow into and out of the groove is characterized by backward step flow and jet flow, respectively. In the structural field, the maximum deformation and the maximum contact pressure of the main sealing surface appear at the notch of the expansion seal ring, and the seal pressure differential has the most significant influence on it. The relative error between the predicted value of the developed model and experimental values is within 9%, which meets the industrial requirements. This work facilitates scholars to understand the internal flow mechanism and deformation process of expanding seal rings and provides a method to predict sealing ring power loss.

Design and experimental investigation of symmetrical embedded magnetic fluid rotary seal with small gap

A novel symmetrical embedded magnetic fluid seal (SEMFS) structure was designed with the aim of enhancing the pressure resistance of the magnetic fluid (MF) seal with small gap under vacuum condition. The magnetic field distribution in the sealing gap (SG) was studied by numerical simulation, and the theoretical pressure resistant-withstanding of the SEMFS was obtained by combining the pressure resistance theories of stepped MFS. An experimental study was conducted to investigate the effects of magnetic fluid injection volume (MFIV), number of pole teeth, SG, and rotational speed of the rotating shaft on the seal's pressure resistance. The pressure resistant-withstanding values obtained were compared with those theoretically projected for the (SEMFS) and the ordinary magnetic fluid seal (OMFS), based on numerical analysis. The results indicate that the measured pressure value for the SEMFS matches well with the calculated pressure value. Furthermore, the SEMFS exhibits superior pressure resistance capabilities compared to the OMFS when subjected to the same parameters, which fully reflects the superiority of SEMFS structure. With an augment in the injection volume of MF, the pressure-withstanding performance of the SEMFS exhibits an initial upward trend followed by a gradual stabilization. Moreover, the pressure-withstanding performance of the SEMFS demonstrates a progressive enhancement with an increase in the number of radial pole teeth (RPT) and a corresponding increment in the number of axial pole teeth (APT). The ability to resist pressure of SEMFS decreases as the radial sealing gap (RSG) and axial sealing gap (ASG) increase. At low shaft speeds, the SEMFS's pressure resistance capability is not impacted by rotational speed and can be considered similar to a static seal.

Analysis of Negative Pressure Sealing Drainage Technology for the Treatment of Orthopedic Trauma Infection

To explore the effective treatment of orthopedic trauma infection, the cases selected were 35 patients with orthopedic trauma infection. The study period was from January 2020 to December 2022. They were divided into the study group (n = 18) and the control group (n = 17) through the double-blind randomization of the medical record numbered envelopes. The patients in the control group were treated with conventional debridement and dressing change, and the patients in the study group were treated with negative pressure sealing drainage technology. The frequency of dressing changes, visual analogue scale (VAS) score, wound healing time, hospitalization time, and good wound healing rate were compared between the two groups. The number of dressing changes, VAS score, wound healing time, and hospitalization time in the study group were lower than those in the control group (P < 0.05), and the rate of good wound healing in the study group was higher than that in the control group (P < 0.05). Negative pressure sealing drainage technology for orthopedic trauma infection patients can decrease the number of dressing changes, reduce pain, accelerate the time for wound healing, shorten hospitalization time, and improve wound healing effect, which has the value of popularization and application.

A systematic review and meta-analysis on the efficacy and safety of the Baska mask versus other laryngeal mask airways during general anaesthesia.

The Baska mask is a supraglottic airway device used during general anaesthesia that combines features from various other devices. This systematic review aims to compare its efficacy and safety with other laryngeal mask airways. Randomised controlled trials were identified by searching PubMed, Scopus, Web of Science and Cochrane Library. RevMan software was used for meta-analysis, with mean difference and risk ratios calculated for continuous and dichotomous data, respectively, along with a 95% confidence interval. The meta-analysis found that the Baska mask provides a better oropharyngeal seal pressure (mean difference = 7.03; 95% confidence interval = [6.00, 8.07], p < 0.00001) and a higher rate of maximal seal pressure (risk ratio = 18.38; 95% confidence interval = [2.53, 133.47], p = 0.004) compared to other laryngeal mask airways. However, the Baska mask had lower success rates in first-attempt insertion (risk ratio = 0.79; 95% confidence interval = [0.72, 0.86], p < 0.00001) and higher rates of insertion manipulation (risk ratio = 16.64; 95% confidence interval = [5.86, 47.24], p < 0.00001). The Baska mask offers better oropharyngeal seal pressure, but may be more difficult to insert than other laryngeal mask airways, without causing significant delays. The Baska mask appears as safe as other laryngeal mask airways, but larger trials are needed to support these findings.

Baska mask vs ProSeal Laryngeal mask on airway seal pressure in cases undergoing general anesthesia by mechanical ventilation: A randomized controlled trial

ABSTRACT Background Supraglottic Airway Devices (SGAs) are designed to counteract the drawbacks of endotracheal intubation. They have proven to be easy to use, robust, versatile, and usable in many difficult situations. This work aims to investigate the use of the Baska Mask (BM) airway and ProSeal™ Laryngeal Mask Airway (PLMA) as SGAs for ventilation. Methods This randomized controlled trial was carried out on 74 cases aged 21–65 years old for elective surgery of a planned duration of up to 2 h during general anaesthesia with intermittent positive pressure ventilation. Cases were divided into two equal groups. Ventilation was done either by BM® Airway (group BM) or PLMA (group PLMA). Results BM had a shorter insertion time and lower leak fraction versus PLMA, while seal pressure elevated significantly with BM versus PLMA (P < 0.001). PLMA had significantly more cases than the BM mask group complaining of a sore throat at 2 h (P = 0.042). Complication after gastric tube insertion was parallel between both groups. Conclusions BM can be used successfully during anesthesia as it displays a shorter insertion time, lower leak fraction, higher seal pressure, and lower incidence of sore throat and gastric tube insertion complications than PLMA.

Research Progress on Pressure Sealing Materials for Fractured Gas Reservoirs

To study a kind of plugging material suitable for gas invasion in gas reservoirs fractured pressure plugging material. Gas invasion in carbonate gas reservoirs is frequent and will be accompanied by lost circulation and overflow, which will affect the safety and efficient production of oil and gas wells, and even cause serious safety hazards. In this regard, this paper summarizes the research process and problems encountered in the application of reverse pressure plugging materials in Carbonate rock fractured gas reservoirs. At the same time, it introduces the types of main plugging materials in the world and the research progress of plugging materials (polymer gel plugging technology, ultra-low permeability (non permeability) drilling fluid technology, etc.), the theory of plugging materials (rigid plugging theory, flexible plugging theory, etc.), as well as the characteristics of typical plugging materials and plugging material technology.

COMPARISON BETWEEN BASKA MASK AND I-Gel INSERTION IN MINOR SURGERIESUNDER GENERAL ANAESTHESIA IN PATIENT AGED 18-50 Y:-A RANDOMIZEDINTERVENTIONAL STUDY

Objective: The supraglottic airway (SAD) is considered a viable alternative to endotracheal intubation, particularly in cases where SAD is not contraindicated. SAD plays a crucial role in difficult airway algorithms, offering unobstructed oxygenation and ventilation, as well as providing hemodynamic stability with minimal laryngopharyngeal morbidity. The LMA-classic, introduced by Archie Brain in 1983, was the first second-generation SAD used in clinical practice. Over time, numerous advancements have led to the development of improved second-generation SADs.&#x0D; Methods: This study aims to compare the efficacy and advantages of different supraglottic airway devices. Two types of second-generation SADs were evaluated:I-gel (Intersurgical, Wokingham, UK) and a novel device called Baska Mask, which belongs to the third generation of SADs. The evaluation criteria included ease of insertion, oropharyngeal sealing pressure, ability to drain gastric fluid, prevention of malposition, sealing pressure during controlled ventilation and spontaneous breathing, and reduction of respiratory complications.&#x0D; Results: The second-generation SADs, including the I-gel, are easy to insert and offer high oropharyngeal sealing pressure. They have a gastric channel to drain gastric fluid, reducing aspiration risk. The I-gel, a new latex-free SAD with a noninflatable cuff made of medical-grade thermoplastic elastomer, provides a superior seal, resulting in lower respiratory complications compared to earlier SADs. It ensures effective sealing during controlled ventilation and spontaneous breathing. The third-generation Baska Mask combines the advantages of second-generation LMAs and provides higher seal pressure during IPPV by apposing to the glottis, distinguishing it from non-inflatable cuff devices like the I-gel.&#x0D; Conclusion: Supraglottic airway devices, particularly second-generation SADs like I-gel, offer effective airway management alternatives to endotracheal intubation. These devices provide ease of insertion, high oropharyngeal sealing pressure, and the ability to drain gastric fluid, reducing the risk of complications. The third-generation device, Baska Mask, exhibits enhanced seal pressure during IPPV, making it a promising advancement in airway management.

Autonomous intelligent control of earth pressure balance shield machine based on deep reinforcement learning

In order to reduce the construction risk caused by human operation error and improve the geological adaptive ability of the shield machine, an autonomous intelligent control method is proposed for shield machine within the framework of interaction–judgment–decision based on Deep Deterministic Policy Gradient (DDPG) deep reinforcement learning in this study. Due to the strong nonlinear relationship between the shield machine's tunneling parameters, this research builds a deep reinforcement learning environment using mechanism model of sealed cabin pressure. DDPG agent model of the shield machine is established to replace the shield machine to interact and train with the geological environment. By minimizing the difference between the target pressure setting value and the sealed cabin pressure value, the dynamic balance between the sealed cabin pressure and the pressure on the excavation surface is realized, and the best strategy is obtained. Through real-time interaction with the geological environment, the method in this paper can dynamically adjust the tunneling parameters, accurately control the sealed cabin pressure, and has a strong geological adaptive ability. By realizing the intelligent decision-making of the tunneling parameters, it greatly improves the independent decision-making ability of the shield machine system, reduces the inaccuracy of human operation, and provides an effective guarantee for the efficient and safe operation of the shield machine. This study applies deep reinforcement learning technology to the control field of earth pressure balance shield machine, promotes AI technology, and provides a new idea for the development of AI construction technology in engineering field.

Magnetic field simulation and experimental investigation of magnetic fluid seal based on rotating shaft

Magnetic fluid seals are a new type of seal with zero leakage. Based on the requirements of the working conditions, a magnetic fluid seal device applicable to rotating shafts was designed in this study using magnetic field simulation analysis and experimental verification. The relationships between several structural variables and seal pressure were analyzed, and the fitting curve and equation were derived via fitting analysis. The magnetic field simulation results showed that sealing pressure decreased with an increase in the sealing gap, increased with the number of pole teeth, and increased and then decreased with an increase in the pole teeth angle. The trapezoidal pole teeth exhibited the best sealing performance. The experimental results showed that the best sealing performance was achieved when the amount of magnetic fluid was 3mL. The sealing pressure significantly decreased with an increase in the rotational speed.

The influence of different offset modes on the drainage characteristics of a double stack drainage system in a high-rise building

To meet the functional requirements of high-rise buildings, drainage stacks usually employ an offset pipe in the structural transfer floor. At the offset point, the flow direction changes and the air pressure fluctuates, which significantly influences the drainage system capacity and water seal effectiveness. Different offset modes have different degrees of influence on drainage characteristics. To better understand the influence of different offset modes on drainage characteristics, five different test conditions in double stack building drainage systems were established and investigated. DS1 was a standard double-stack drainage system with anti-reflux H-tube joints for every two floor levels. The remaining four systems were developed from DS1 by adopting various offset pipes (or pipe joints) on the fourth floor. DS2 adopted an S-shape offset pipe joint at the offset point. DS3 adopted double S-shape offset pipe joints. DS4 adopted a 1.0-m-long horizontal offset pipe. DS5 adopted a 1.5-m-long horizontal offset pipe. The pressure fluctuations and water seal losses were chosen as the experimental parameters to determine the maximum discharge capacity according to the Standard for Capacity Test of Vertical Pipe of the Domestic Residential Drainage System CJJ/T 245. The experimental results demonstrated that the installation of offset pipes (or pipe joints) contributed to the abrupt positive pressure and severe water seal losses at the position where flow direction shifted. As the length of the offset pipe increased, the positive pressure was more severe, and maximum discharge capacity was minor. The relationships among the maximum discharge rate, pressure fluctuation limits, and water seal losses are discussed. Lastly, a nondimensional analysis was adopted to understand the relationship between water seal losses and pressure limit values under different discharge rates for current test facilities. Practical application: Pipe offset has the potential to influence a drainage system discharge capacity. As the length of the horizontal offset pipe increases, the discharge capacity will decrease. In the actual design, the length of the offset pipe section should be reduced and this study demonstrates that the application of S-shape offset pipe joints is an efficient solution.

South Anze Structure and Its Control on Coalbed Methane Aggregation in the Qinshui Basin and the Mechanism of Syncline Gas Enrichment in the Qinshui Basin

The phenomenon of coalbed-methane synclinal accumulation in the Qinshui Basin has been widely reported, but it has mainly been observed in the core block of the Qinshui Syncline. The questions arise: does this phenomenon exist in the wing of the Qinshui Syncline and, if so, what is the mechanism behind it? Further study is required to answer these questions. This paper focuses on the South Anze No. 3 coal seam in the Qinshui Basin as an example. It conducts a systematic sorting of coalbed-methane geological characteristics and an analysis of the effects of structural assemblage characteristics, genetic mechanisms, and structural control on coalbed-methane accumulation. Additionally, it examines the basin structure and evolution during the critical period of the Qinshui Basin, as well as the gas geological characteristics of adjacent areas, in order to discuss the gas-rich mechanism of the syncline in the Qinshui Basin. Key insights obtained from the study include the following: (i) The whole South Anze is a nosing structure that plunges from west to east and superposes secondary folds and faults in different directions. Four deformation zones can be identified based on the characteristics of structural assemblage, including NEN-oriented compressive structures, ENE-trend shear fractures, EW-trend compressive fractures, and EW-trend compressive folds. The formation of structural assemblage in the study area is attributed to the compression in the Indosinian and Yanshanian, and the fault inversion in the Himalayan period. (ii) The ENE-trend shear fracture deformation area located in the nosing uplift is a low CBM (coalbed methane) content area due to gas diffusion during the Himalayan extension. The syncline in the combination of NEN-trend and EW-trend “ejective folds” in the west and south of the study area is a high-value area of coalbed-methane content. It is further verified that the law of syncline gas accumulation in the Qinshui Basin is also applicable to the wing of the Qinshui Syncline. (iii) Since the formation of the Qinshui Syncline, the main coal seam has been in an extensional environment below the neutral plane, resulting in the main dissipation of coalbed methane. During its geological history, surface water penetrated the aquifer above the main coal seam through two channels: the extensional area above the neutral plane of the adjacent anticline and the shear fracture. A hydrostatic pressure seal is formed in the Qinshui Syncline and the secondary syncline is superimposed upon it, which is the cause of gas enrichment in the syncline of the Qinshui Basin. (iv) Weak deformation in the syncline basin is the focus of global coalbed-methane exploration and development. The mechanism proposed in this paper can provide ideas and references for further understanding of coalbed-methane enrichment in this type of basin.

Comparison of clinical performance of Ambu® AuraGain™ and BlockBuster® in anaesthetised preschool children-A randomised controlled trial.

Supraglottic airway (SGA) devices are a boon to paediatric airway management. The clinical performances of the BlockBuster® laryngeal mask airway (LMA) and Ambu® AuraGain™ in preschool children were compared in this study. After ethical approval and trial registration, this randomised controlled study was conducted on 50 children, aged 1-4 years, randomised into two groups. Appropriate sized Ambu® AuraGain™ (group A) and LMA BlockBuster® (group B) were placed as per the manufacturer's recommendation under general anaesthesia. Appropriate size of the endotracheal tube was then chosen and inserted through the device. Primary objective of the study was to compare the oropharyngeal seal pressure (OSP), and secondary objectives were the first attempt intubation success rate, overall intubation success rate, SGA insertion time, intubation time, haemodynamic changes and postoperative pharyngolaryngeal complications. The Chi-square test was used to analyse the categorical variables, while the intragroup comparison of mean changes in outcomes was evaluated by the unpaired t-test. The level of significance was set at P < 0.05. Demographic parameters were uniformly distributed in both the groups. The mean OSP in group A was 26.6 ± 0.95 cm H2O and in group B was 29.08 ± 0.75 cm H2O. Both the devices were successfully inserted in all the patients. The success rate of blind endotracheal intubation through the device in first attempt was 4% in group A and 80% in group B. Postoperative pharyngolaryngeal complications were relatively less in group B. LMA BlockBuster® provides higher OSP and provides a higher success rate of blind endotracheal intubation in paediatric patients.

Thermo-Hydrodynamic Lubricating Behaviors of Upstream Liquid Face Seals with Ellipse Dimples.

In order to obtain the leakage characteristics of an upstream pumping face seal with inclined ellipse dimples under high-temperature and high-speed liquid lubricating conditions, a thermo-hydrodynamic lubricating model is developed. The novelty of this model is that it takes the thermo-viscosity effect and cavitation effect into account. The influence of operating parameters, such as rotational speed, seal clearance, seal pressure, ambient temperature and structural parameters, such as dimple depth, inclination angle, slender ratio and dimple number on the opening force and leakage rate, is numerically calculated. The results obtained show that the thermo-viscosity effect makes the cavitation intensity decrease noticeably, leading to an increase in the upstream pumping effect of ellipse dimples. Moreover, the thermo-viscosity effect may make both the upstream pumping leakage rate and opening force increase by about 10%. It can also be found that the inclined ellipse dimples can produce an obvious upstream pumping effect and hydrodynamic effect. Based on the reasonable design of the dimple parameter, not only can the sealed medium achieve zero leakage, but the opening force can also increase by more than 50%. The proposed model has the potential to provide the theoretical basis for and guide the future designs of upstreaming liquid face seals.

Thermal Runaway Vent Gases from High-Capacity Energy Storage LiFePO4 Lithium Iron

Lithium batteries are being utilized more widely, increasing the focus on their thermal safety, which is primarily brought on by their thermal runaway. This paper’s focus is the energy storage power station’s 50 Ah lithium iron phosphate battery. An in situ eruption study was conducted in an inert environment, while a thermal runaway experiment was conducted utilizing sealed pressure containers and an external heating triggering mechanism. Both the amount of gas release and the battery’s maximum temperature were discovered. Using gas chromatography, the gas emission from the battery was examined. Its principal constituents included CO, H2, CO2, CH4, C2H4, and so on. Moreover, the experiment discovered a second eruption of lithium iron phosphate, and the stage of its eruption was separated by the pressure signal of the sealed experimental chamber, giving a theoretical foundation and technological backing for the thermal catastrophe safety of lithium batteries.

Comparison of Baska Mask Versus Proseal Laryngeal Mask Airway in Elective Surgeries Under General Anaesthesia: A Randomized Clinical Trial.

Background Baska Mask (BM) is a third-generation supraglottic airway device with a self-inflating cuff. This study aimed to evaluate the efficacy of the BM compared to ProSeal laryngeal mask airway (PLMA) regarding insertion time, ease of insertion, and oropharyngeal seal pressure in patients undergoing elective surgeries under general anesthesia for less than two hours. Methods This prospective, randomized, double-blind comparative study was done on 64 patients randomly divided into two groups, with 32 patients in the PLMAgroup (Group A) and 32 in the BM group (Group B). Individuals with a body mass index (BMI)of more than 30, a history of nausea/vomiting, or pharyngeal pathology were excluded from the trial. After induction with propofol 3-4 mg/kg, fentanyl 1-2 mcg/kg, and the neuromuscular blockade was achieved with atracurium 0.5 mg/kg, patientswere insertedwitheither BM (n= 32) or PLMA (n= 32). The primary outcome measure was the time taken for insertion and ease of insertion. Secondary outcome measures included the number of attempts, oropharyngeal seal pressure (OSP), and laryngopharyngeal morbidity (trauma to lips, blood staining, and sore throat) immediately and 24 hours postoperatively. Results Demographic data were comparable and statistically insignificant. Regarding time and ease of insertion, the BM could be inserted in a lesser time of 24±1.136 seconds compared to PLMA which took 28.59±1.682 seconds, with a high success rate in the first attempt which wasstatistically significant. The BMprovided a higher OSP(31.34 +1.638 cmH2O)when compared to PLMA(24.81±1.469 cmH2O) andwas statistically significant. Complications associated with insertion trauma to the lip, blood staining, and sore throat were more in PLMA (15.6%, 15.6 %, 9.4%, respectively) compared to the BM (6.3%, 3.1%, 3.1%, respectively), and statistically insignificant. Conclusion BM had higher first-attempt successful insertion with better OSP compared to PLMAin patients under controlled ventilation.

Effect of shaft speed on performance of magnetic fluid seal with gas isolation for sealing water

When applied to seal liquid, magnetic fluid seal was prone to failure with the increase of shaft speed because of instability at the interface of these two fluids caused by shaft rotation. In order to avoid this problem, a new type of magnetic fluid seal was proposed, in which the magnetic fluid was separated from the sealed liquid by gas. The sealing principle of the structure was studied. Gas-liquid two-phase flow in the structure was simulated by computational fluid dynamics. A test rig of magnetic fluid seal with gas isolation was set up. Experiments of pressure resistance and seal durability of the original structure and structure with gas isolation for sealing water were carried out on the test bench. The results of theoretical analysis, CFD and experiments indicated that: there was no obvious relationship between shaft speed and performance of magnetic fluid seal when gas isolation was added for sealing water. Its pressure resistance was almost the same as that of the structure sealing gas. Its seal durability was significantly longer.

Cold Spray metal powder deposition with 9 %Cr-steel applied for the HCPB First Wall fabrication: Proof of concept and options for ODS steel processing

At the KIT a hybrid manufacturing concept for nuclear fusion First Walls is developed combining aspects of conventional and Additive Manufacturing (AM) technologies. The state of the art for ITER does not cover all specifications of a DEMO relevant First Wall. Thus, additional R&D-work has been initiated in terms of manufacturing. The AM technology basis used in the presented process combination is Cold Spray metal powder deposition applied in alternation with machining including the feature of filling grooves temporarily with a water-soluble granulate for creation of closed channels and cavities. Thus, the technology provides the option to manufacture shells with a thin gas tight membrane on top of previously machined structures. This membrane is used as pressure seal and makes the joining of shells by Hot Isostatic Pressing (HIP) into one monolithic body possible. This paper describes the manufacturing process and recalls differences and common aspects with regard to conventional concepts of First Wall manufacturing. The achievement of Technology Readiness Level TRL 3 by mechanical qualification and comparison of the results to other HIP joint experiments is also demonstrated. Finally, an outlook is given concerning integration options of the technology into manufacturing of shells with cooling channel structures using Oxide Dispersion Strengthened (ODS) materials.